arm32: itx: Add a NEON implementation of itx for 10 bpc

Relative speedup vs C for a few functions:

                                      Cortex A7     A8     A9    A53    A72    A73
inv_txfm_add_4x4_dct_dct_0_10bpc_neon:     2.79   5.08   2.99   2.83   3.49   4.44
inv_txfm_add_4x4_dct_dct_1_10bpc_neon:     5.74   9.43   5.72   7.19   6.73   6.92
inv_txfm_add_8x8_dct_dct_0_10bpc_neon:     3.13   3.68   2.79   3.25   3.21   3.33
inv_txfm_add_8x8_dct_dct_1_10bpc_neon:     7.09  10.41   7.00  10.55   8.06   9.02
inv_txfm_add_16x16_dct_dct_0_10bpc_neon:   5.01   6.76   4.56   5.58   5.52   2.97
inv_txfm_add_16x16_dct_dct_1_10bpc_neon:   8.62  12.48  13.71  11.75  15.94  16.86
inv_txfm_add_16x16_dct_dct_2_10bpc_neon:   6.05   8.81   6.13   8.18   7.90  12.27
inv_txfm_add_32x32_dct_dct_0_10bpc_neon:   2.90   3.90   2.16   2.63   3.56   2.74
inv_txfm_add_32x32_dct_dct_1_10bpc_neon:  13.57  17.00  13.30  13.76  14.54  17.08
inv_txfm_add_32x32_dct_dct_2_10bpc_neon:   8.29  10.54   8.05  10.68  12.75  14.36
inv_txfm_add_32x32_dct_dct_3_10bpc_neon:   6.78   8.40   7.60  10.12   8.97  12.96
inv_txfm_add_32x32_dct_dct_4_10bpc_neon:   6.48   6.74   6.00   7.38   7.67   9.70
inv_txfm_add_64x64_dct_dct_0_10bpc_neon:   3.02   4.59   2.21   2.65   3.36   2.47
inv_txfm_add_64x64_dct_dct_1_10bpc_neon:   9.86  11.30   9.14  13.80  12.46  14.83
inv_txfm_add_64x64_dct_dct_2_10bpc_neon:   8.65   9.76   7.60  12.05  10.55  12.62
inv_txfm_add_64x64_dct_dct_3_10bpc_neon:   7.78   8.65   6.98  10.63   9.15  11.73
inv_txfm_add_64x64_dct_dct_4_10bpc_neon:   6.61   7.01   5.52   8.41   8.33   9.69
37 jobs for arm32-itx16 in 9 minutes and 30 seconds (queued for 3 minutes and 4 seconds)
Status Job ID Name Coverage
  Style
passed #576170
amd64 docker
style-check

00:00:06

passed #576171
amd64 docker
x86inc-check

00:00:05

 
  Build
passed #576185
amd64 docker
build-android-aarch64

00:00:25

passed #576184
amd64 docker
build-android-armv7

00:00:11

passed #576172
amd64 avx2 docker
build-debian

00:00:38

passed #576186
aarch64 docker
build-debian-aarch64

00:00:17

passed #576187
aarch64 docker
build-debian-aarch64-clang-5

00:00:14

passed #576190
armv7 docker
build-debian-armv7

00:00:53

passed #576191
armv7 docker
build-debian-armv7-clang-5

00:00:38

passed #576178
amd64 docker
build-debian-bitdepth-16

00:00:13

passed #576177
amd64 docker
build-debian-bitdepth-8

00:00:27

passed #576175
amd64 docker
build-debian-examples

00:00:25

passed #576176
amd64 docker
build-debian-no-tools

00:00:32

passed #576193
ppc64le docker
build-debian-ppc64le

00:01:18

passed #576173
amd64 docker
build-debian-static

00:00:29

passed #576189
aarch64 docker
build-debian-werror

00:00:09

passed #576174
amd64 docker
build-debian32

00:00:31

passed #576188
catalina amd64
build-macos

00:00:38

passed #576194
amd64 docker
build-pages

00:00:21

passed #576192
amd64 docker
build-ubuntu-snap

00:00:24

passed #576182
amd64 docker
build-win-arm32

00:00:10

passed #576183
amd64 docker
build-win-arm64

00:00:23

passed #576179
amd64 docker
build-win32

00:00:31

passed #576180
amd64 docker
build-win32-unaligned-stack

00:00:26

passed #576181
amd64 docker
build-win64

00:00:41

 
  Test
passed #576195
amd64 docker
test-debian

00:01:28

95.8333%
passed #576204
aarch64 docker
test-debian-aarch64

00:00:26

passed #576206
armv7 docker
test-debian-armv7-clang-5

00:01:15

passed #576199
amd64 docker
test-debian-asan

00:02:00

passed #576196
avx2 amd64 docker
test-debian-asm

00:01:00

passed #576200
amd64 docker
test-debian-msan

00:01:08

passed #576205
ppc64le docker
test-debian-ppc64le

00:02:22

passed #576202
amd64 docker
test-debian-tsan

00:04:28

passed #576201
amd64 docker
test-debian-ubsan

00:02:10

passed #576198
amd64 avx2 docker
test-debian-unaligned-stack

00:00:51

passed #576197
avx2 amd64 docker
test-debian32-asm

00:01:05

passed #576203
amd64 avx2 docker
test-win64

00:01:09