Revert "drm/dp: Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUS"

This reverts commit 944e732 which is
commit a40c5d7 upstream.

The upstream commit a40c5d7 ("drm/dp:
Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUS") the
reverted commit backported causes a regression, on one eDP panel at
least resulting in display flickering, described in detail at the Link:
below. The issue fixed by the upstream commit will need a different
solution, revert the backport for now.

Cc: [email protected]
Cc: [email protected]
Cc: Sasha Levin <[email protected]>
Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14558
Signed-off-by: Imre Deak <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: ideak

drivers/gpu/drm/display/drm_dp_helper.c

@@ -725,7 +725,7 @@ ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset,
 	 * monitor doesn't power down exactly after the throw away read.
 	 */
 	if (!aux->is_remote) {
-		ret = drm_dp_dpcd_probe(aux, DP_LANE0_1_STATUS);
+		ret = drm_dp_dpcd_probe(aux, DP_DPCD_REV);
 		if (ret < 0)
 			return ret;
 	}