staging: xgifb: update TODO

There are no build warnings at the moment.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/xgifb/TODO

@@ -5,7 +5,6 @@ Arnaud
 
 TODO:
 - clean ups
-- fix build warnings when module
 - sort out dup ids with SiS driver
 - remove useless/wrong/unused #ifdef/code/...
 - fix printk usages