drm/amd/display: Fix the checking condition in dmub aux handling

[Why & How]
Fix the checking condition for detecting AUX_RET_ERROR_PROTOCOL_ERROR.
It was wrongly checking by "not equals to"

Reviewed-by: Ray Wu <ray.wu@amd.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 1db6c9e)
Cc: stable@vger.kernel.org

Author: Wayne Lin

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

@@ -12749,7 +12749,7 @@ int amdgpu_dm_process_dmub_aux_transfer_sync(
 		 * Transient states before tunneling is enabled could
 		 * lead to this error. We can ignore this for now.
 		 */
-		if (p_notify->result != AUX_RET_ERROR_PROTOCOL_ERROR) {
+		if (p_notify->result == AUX_RET_ERROR_PROTOCOL_ERROR) {
 			DRM_WARN("DPIA AUX failed on 0x%x(%d), error %d\n",
 					payload->address, payload->length,
 					p_notify->result);