drm/amd/display: Assign linear_pitch_alignment even for VM

[Description]
Assign linear_pitch_alignment so we don't cause a divide by 0
error in VM environments

Reviewed-by: Sohaib Nadeem <sohaib.nadeem@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Alvin Lee <alvin.lee2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>