drm/amd/display: stop using connector->override_edid

drm/amd/display: stop using connector->override_edid

The connector->override_edid flag is strictly for EDID override debugfs
management, and drivers have no business using it.

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Xinhui Pan <Xinhui.Pan@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Alex Deucher <alexdeucher@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c901869ff8a4e3aebc4abec99c7dd7b4c224f6e6.1666614699.git.jani.nikula@intel.com