staging: xgifb: Update TODO

staging: xgifb: Update TODO

There's no more printk abuse, it's been sorted out in
448810662ac3 ("Staging: xgifb: Remove printk usage.")

Extra ifdefs have been fixed too, mostly in
800d67cf9f77 ("staging: xgifb: eliminate #ifdef Tap4"),
c39aada6926c ("staging: xgifb: eliminate #ifdef XGIFB_PAN"),
fa4c212f2b81 ("staging: xgifb: delete unused definitions"),
5c167b30c1b4 ("staging: xgifb: eliminate #ifdef NewScratch"),
f059077388b0 ("Staging: xgifb: Remove #ifdef MODULE") and more.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>