multimedia/x264: fix build with llvm 16

common/ppc/pixel.c:1576:31: error: incompatible function pointer types assigning to 'x264_pixel_cmp_x3_t' (aka 'void (*)(unsigned char *, unsigned char *, unsigned char *, unsigned char *, long, int *)') from 'int (uint8_t *, uint8_t *, uint8_t *, uint8_t *, intptr_t, int *)' (aka 'int (unsigned char *, unsigned char *, unsigned char *, unsigned char *, long, int *)') [-Wincompatible-function-pointer-types]

pixf->sad_x3[PIXEL_8x16]  = pixel_sad_x3_8x16_altivec;
                          ^ ~~~~~~~~~~~~~~~~~~~~~~~~~

common/ppc/pixel.c:1578:31: error: incompatible function pointer types assigning to 'x264_pixel_cmp_x3_t' (aka 'void (*)(unsigned char *, unsigned char *, unsigned char *, unsigned char *, long, int *)') from 'int (uint8_t *, uint8_t *, uint8_t *, uint8_t *, intptr_t, int *)' (aka 'int (unsigned char *, unsigned char *, unsigned char *, unsigned char *, long, int *)') [-Wincompatible-function-pointer-types]

pixf->sad_x3[PIXEL_8x8]   = pixel_sad_x3_8x8_altivec;
                          ^ ~~~~~~~~~~~~~~~~~~~~~~~~

common/ppc/pixel.c:1581:31: error: incompatible function pointer types assigning to 'x264_pixel_cmp_x4_t' (aka 'void (*)(unsigned char *, unsigned char *, unsigned char *, unsigned char *, unsigned char *, long, int *)') from 'int (uint8_t *, uint8_t *, uint8_t *, uint8_t *, uint8_t *, intptr_t, int *)' (aka 'int (unsigned char *, unsigned char *, unsigned char *, unsigned char *, unsigned char *, long, int *)') [-Wincompatible-function-pointer-types]

pixf->sad_x4[PIXEL_8x16]  = pixel_sad_x4_8x16_altivec;
                          ^ ~~~~~~~~~~~~~~~~~~~~~~~~~

common/ppc/pixel.c:1583:31: error: incompatible function pointer types assigning to 'x264_pixel_cmp_x4_t' (aka 'void (*)(unsigned char *, unsigned char *, unsigned char *, unsigned char *, unsigned char *, long, int *)') from 'int (uint8_t *, uint8_t *, uint8_t *, uint8_t *, uint8_t *, intptr_t, int *)' (aka 'int (unsigned char *, unsigned char *, unsigned char *, unsigned char *, unsigned char *, long, int *)') [-Wincompatible-function-pointer-types]

pixf->sad_x4[PIXEL_8x8]   = pixel_sad_x4_8x8_altivec;
                          ^ ~~~~~~~~~~~~~~~~~~~~~~~~