aarch64: pixel: add 10bits sad functions

Provide routines for sad functions for high bit depth, i.e. 10 bits. Benchmarks run on AWS Gravtion 2 instances.

sad_4x4_c: 586 sad_4x4_neon: 275 sad_4x8_c: 1194 sad_4x8_neon: 362 sad_4x16_c: 2079 sad_4x16_neon: 552 sad_8x4_c: 955 sad_8x4_neon: 209 sad_8x8_c: 1719 sad_8x8_neon: 311 sad_8x16_c: 3533 sad_8x16_neon: 496 sad_16x8_c: 3084 sad_16x8_neon: 629 sad_16x16_c: 6055 sad_16x16_neon: 1111

Signed-off-by: Hubert Mazur hum@semihalf.com Signed-off-by: Grzegorz Bernacki gjb@semihalf.com