Revert "drm/amd/display: fix dereferencing possible ERR_PTR()"

This reverts commit cd2d6c9.

Cc: Shirish S <shirish.s@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -4864,9 +4864,6 @@ static int dm_atomic_check_plane_state_fb(struct drm_atomic_state *state,
 			return -EDEADLK;
 
 		crtc_state = drm_atomic_get_crtc_state(plane_state->state, crtc);
-		if (IS_ERR(crtc_state))
-			return PTR_ERR(crtc_state);
-
 		if (crtc->primary == plane && crtc_state->active) {
 			if (!plane_state->fb)
 				return -EINVAL;