drm/amd/display: Remove power sequencing check

[Why]
	Some ASICs keep backlight powered on after dpms off
	command has been issued.

[How]
	The check for no edp power sequencing was never going to pass.
	The value is never changed from what it is set by design.

Cc: stable@vger.kernel.org # 6.1+
Link: drm/amd#2765


Reviewed-by: Swapnil Patel <swapnil.patel@amd.com>
Acked-by: Roman Li <roman.li@amd.com>
Signed-off-by: Agustin Gutierrez <agustin.gutierrez@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>