drm/amd/display: Connect dig_fe to otg directly instead of calling bios

[Why] After call bios table crtc_source_select, dal will program fmt
again. The bios table program dig_source_select and other fmt register
for bios usage which is redundancy and uncessary.

[How] Program dig_soruce_select register directly

Signed-off-by: hersen wu <hersenxs.wu@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>