drm/amd/display: Fix eDP receiver ready status check in T7 sequence

drm/amd/display: Fix eDP receiver ready status check in T7 sequence

[Why]
Some eDP panels return sinkstatus as 0x5, causing the original sinkstatus == 1
check to never match and resulting in unnecessary polling delay. The
equality check is too restrictive and doesn't properly validate the
specific status bit that indicates receiver readiness.

[How]
Replace direct value comparison with proper bitmask check using
DP_RECEIVE_PORT_0_STATUS constant.

Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Sung-huai Wang <Danny.Wang@amd.com>
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>