drm/radeon/kms: make an aux failure debug only

Can happen when there is no DP panel attached, confusing
users.  Make it debug only.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/atombios_dp.c

@@ -283,7 +283,7 @@ int radeon_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
 		}
 	}
 
-	DRM_ERROR("aux i2c too many retries, giving up\n");
+	DRM_DEBUG_KMS("aux i2c too many retries, giving up\n");
 	return -EREMOTEIO;
 }