Revert "drm/amd/display: Fix incorrect pointer assignment"

This reverts commit 0a571e86.

[Why]
The change being reverted incorrectly assumes that a pointer type was
intended, however copying to a new structure is correct. As well, there
is no compiler error, it was instead an error in the testing framework
being used.

Reviewed-by: Chaitanya Dhere <chaitanya.dhere@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Joshua Aberback <joshua.aberback@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>