riscv64/mc: Add w_mask functions

Closes: !1801 (closed) !1805 (closed) !1806 (closed) !1797

Merged work of !1801 (closed), !1805 (closed), !1806 (closed)

Benchmarks:

Kendryte K230

SpacemiT K1

w_mask_420_w4_8bpc_c: 845.1 ( 1.00x) w_mask_420_w4_8bpc_rvv: 313.1 ( 2.70x) w_mask_420_w8_8bpc_c: 2589.9 ( 1.00x) w_mask_420_w8_8bpc_rvv: 549.3 ( 4.72x) w_mask_420_w16_8bpc_c: 8389.9 ( 1.00x) w_mask_420_w16_8bpc_rvv: 1250.4 ( 6.71x) w_mask_420_w32_8bpc_c: 33485.7 ( 1.00x) w_mask_420_w32_8bpc_rvv: 4276.9 ( 7.83x) w_mask_420_w64_8bpc_c: 81934.2 ( 1.00x) w_mask_420_w64_8bpc_rvv: 11243.9 ( 7.29x) w_mask_420_w128_8bpc_c: 205865.8 ( 1.00x) w_mask_420_w128_8bpc_rvv: 28098.0 ( 7.33x) w_mask_422_w4_8bpc_c: 838.6 ( 1.00x) w_mask_422_w4_8bpc_rvv: 315.9 ( 2.65x) w_mask_422_w8_8bpc_c: 2576.4 ( 1.00x) w_mask_422_w8_8bpc_rvv: 564.2 ( 4.57x) w_mask_422_w16_8bpc_c: 8378.7 ( 1.00x) w_mask_422_w16_8bpc_rvv: 1305.4 ( 6.42x) w_mask_422_w32_8bpc_c: 33512.4 ( 1.00x) w_mask_422_w32_8bpc_rvv: 4487.6 ( 7.47x) w_mask_422_w64_8bpc_c: 82489.8 ( 1.00x) w_mask_422_w64_8bpc_rvv: 11895.3 ( 6.93x) w_mask_422_w128_8bpc_c: 207116.2 ( 1.00x) w_mask_422_w128_8bpc_rvv: 29541.4 ( 7.01x) w_mask_444_w4_8bpc_c: 822.7 ( 1.00x) w_mask_444_w4_8bpc_rvv: 265.3 ( 3.10x) w_mask_444_w8_8bpc_c: 2542.5 ( 1.00x) w_mask_444_w8_8bpc_rvv: 429.2 ( 5.92x) w_mask_444_w16_8bpc_c: 8290.8 ( 1.00x) w_mask_444_w16_8bpc_rvv: 965.7 ( 8.59x) w_mask_444_w32_8bpc_c: 33229.6 ( 1.00x) w_mask_444_w32_8bpc_rvv: 3289.2 (10.10x) w_mask_444_w64_8bpc_c: 81404.6 ( 1.00x) w_mask_444_w64_8bpc_rvv: 9126.6 ( 8.92x) w_mask_444_w128_8bpc_c: 204438.4 ( 1.00x) w_mask_444_w128_8bpc_rvv: 22424.9 ( 9.12x)

w_mask_420_w4_8bpc_c: 747.9 ( 1.00x) w_mask_420_w4_8bpc_rvv: 290.4 ( 2.58x) w_mask_420_w8_8bpc_c: 2312.3 ( 1.00x) w_mask_420_w8_8bpc_rvv: 478.9 ( 4.83x) w_mask_420_w16_8bpc_c: 7509.3 ( 1.00x) w_mask_420_w16_8bpc_rvv: 885.2 ( 8.48x) w_mask_420_w32_8bpc_c: 30087.8 ( 1.00x) w_mask_420_w32_8bpc_rvv: 2595.6 (11.59x) w_mask_420_w64_8bpc_c: 72313.0 ( 1.00x) w_mask_420_w64_8bpc_rvv: 6020.9 (12.01x) w_mask_420_w128_8bpc_c: 179297.0 ( 1.00x) w_mask_420_w128_8bpc_rvv: 15659.1 (11.45x) w_mask_422_w4_8bpc_c: 735.0 ( 1.00x) w_mask_422_w4_8bpc_rvv: 299.0 ( 2.46x) w_mask_422_w8_8bpc_c: 2285.6 ( 1.00x) w_mask_422_w8_8bpc_rvv: 488.5 ( 4.68x) w_mask_422_w16_8bpc_c: 7459.3 ( 1.00x) w_mask_422_w16_8bpc_rvv: 946.3 ( 7.88x) w_mask_422_w32_8bpc_c: 29996.7 ( 1.00x) w_mask_422_w32_8bpc_rvv: 2812.7 (10.66x) w_mask_422_w64_8bpc_c: 71809.4 ( 1.00x) w_mask_422_w64_8bpc_rvv: 6253.7 (11.48x) w_mask_422_w128_8bpc_c: 178081.9 ( 1.00x) w_mask_422_w128_8bpc_rvv: 16087.8 (11.07x) w_mask_444_w4_8bpc_c: 726.2 ( 1.00x) w_mask_444_w4_8bpc_rvv: 255.9 ( 2.84x) w_mask_444_w8_8bpc_c: 2250.7 ( 1.00x) w_mask_444_w8_8bpc_rvv: 403.9 ( 5.57x) w_mask_444_w16_8bpc_c: 7341.4 ( 1.00x) w_mask_444_w16_8bpc_rvv: 744.7 ( 9.86x) w_mask_444_w32_8bpc_c: 29658.4 ( 1.00x) w_mask_444_w32_8bpc_rvv: 2295.9 (12.92x) w_mask_444_w64_8bpc_c: 70695.9 ( 1.00x) w_mask_444_w64_8bpc_rvv: 4879.0 (14.49x) w_mask_444_w128_8bpc_c: 175483.6 ( 1.00x) w_mask_444_w128_8bpc_rvv: 13021.9 (13.48x)