drm/radeon/kms/dp: fix return in dpcd retrival.

Not returning here caused us to get a display port version of 0 for everything
this caused power up to not get sent which ends up in a black screen.

Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/atombios_dp.c

@@ -459,6 +459,7 @@ void radeon_dp_getdpcd(struct radeon_connector *radeon_connector)
 				printk("%02x ", msg[i]);
 			printk("\n");
 		}
+		return;
 	}
 	dig_connector->dpcd[0] = 0;
 	return;