staging: xgifb: delete duplicated YFilter2 data

All four "YFilter2" tables are identical. Replace as follows:

	NTSCYFilter2	==> xgifb_yfilter2;
	PALMYFilter2	==> xgifb_yfilter2;
	PALNYFilter2	==> xgifb_yfilter2;
	PALYFilter2	==> xgifb_yfilter2;

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