drm/amd/display: Do not skip FBC init in failsafe mode

Initially FBC would be initialized if display's edid was correct
and all the modes acquired from it, but n case when edid is corrupted
or non-existant we must still initialize FBC.

Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>