staging: gdm72xx: fix build errors

This fixes the build errors in the dev_dbg() fixes in a previous patch.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
To: Michalis Pappas <mpappas@fastmail.fm>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>