drm/amd/display: Remove byte swapping for dmcub abm config table

[Why]
Since x86 and dmcub are both little endian, byte swapping isn't
necessary. Dmcu requires byte swapping as it is big endian.

[How]
Add flag to function definitions to determine if byte swapping is
necessary.

Signed-off-by: Wyatt Wood <wyatt.wood@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>