Staging: xgifb: XGI_main_26.c: non-standard C

Fixes following checkpatch warning:

	"WARNING: %Lx is non-standard C, use %llx"

Signed-off-by: Manoj Sawai <mas@iitkgp.ac.in>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>