staging: xgifb: vb_setmode: clean up a single statement if

Eliminate the only remaining checkpatch.pl warning:

	WARNING: braces {} are not necessary for single statement blocks
	#7463: FILE: staging/xgifb/vb_setmode.c:7463:
	+       if (ModeNo & 0x80) {
	+               ModeNo = ModeNo & 0x7F;
	+       }

	total: 0 errors, 1 warnings, 0 checks, 7554 lines checked

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