staging: xgifb: add missing #include

Add a missing include to eliminate the following sparse warning:

drivers/staging/xgifb/vb_table.h:2572:28: warning: symbol 'XGI21_LCDCapList' was not declared. Should it be static?
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/xgifb/vb_setmode.c

@@ -8,6 +8,7 @@
 #include "vb_def.h"
 #include "vgatypes.h"
 #include "vb_struct.h"
+#include "vb_init.h"
 #include "vb_util.h"
 #include "vb_table.h"
 #include "vb_setmode.h"