ppc: Split the cdef_filter in pri/sec as done for the other arches

from

cdef_filter_4x4_01_8bpc_vsx:     86.2 ( 1.84x)
cdef_filter_4x4_10_8bpc_vsx:     72.4 ( 1.49x)
cdef_filter_4x4_11_8bpc_vsx:    102.1 ( 2.98x)
cdef_filter_4x8_01_8bpc_vsx:    153.2 ( 1.96x)
cdef_filter_4x8_10_8bpc_vsx:    116.7 ( 1.75x)
cdef_filter_4x8_11_8bpc_vsx:    181.6 ( 3.26x)
cdef_filter_8x8_01_8bpc_vsx:    232.7 ( 2.53x)
cdef_filter_8x8_10_8bpc_vsx:    174.5 ( 2.18x)
cdef_filter_8x8_11_8bpc_vsx:    282.3 ( 4.10x)

to

cdef_filter_4x4_01_8bpc_vsx:     53.9 ( 2.95x)
cdef_filter_4x4_10_8bpc_vsx:     41.2 ( 2.63x)
cdef_filter_4x4_11_8bpc_vsx:     78.1 ( 3.90x)
cdef_filter_4x8_01_8bpc_vsx:     80.6 ( 3.73x)
cdef_filter_4x8_10_8bpc_vsx:     62.7 ( 3.25x)
cdef_filter_4x8_11_8bpc_vsx:    145.6 ( 4.07x)
cdef_filter_8x8_01_8bpc_vsx:    131.1 ( 4.50x)
cdef_filter_8x8_10_8bpc_vsx:     91.0 ( 4.14x)
cdef_filter_8x8_11_8bpc_vsx:    229.5 ( 5.04x)