staging: xgifb: Update TODO

staging: xgifb: Update TODO

There's no more printk abuse, it's been sorted out in
a5289974f0cf ("Staging: xgifb: Remove printk usage.")

Extra ifdefs have been fixed too, mostly in
113fa1c2d157 ("staging: xgifb: eliminate #ifdef Tap4"),
7a65e81d9055 ("staging: xgifb: eliminate #ifdef XGIFB_PAN"),
1c92864d8761 ("staging: xgifb: delete unused definitions"),
2336d5974211 ("staging: xgifb: eliminate #ifdef NewScratch"),
cbee9eb63e19 ("Staging: xgifb: Remove #ifdef MODULE") and more.

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