x86: add missing initializations for high bit-depth variance

Signed-off-by: James Almer <jamrial@gmail.com>
x86: add missing initialization for high bit-depth sa8d_satd

Signed-off-by: James Almer <jamrial@gmail.com>
x86util: XOP optimized HADDD

Signed-off-by: James Almer <jamrial@gmail.com>
x86: XOP pixel_ssd_nv12_core

Signed-off-by: James Almer <jamrial@gmail.com>
x86: XOP pixel_sad_{x3, x4} high bit-depth

Signed-off-by: James Almer <jamrial@gmail.com>