Staging: XGI: remove duplicated #include

Remove duplicated #include('s) in
  drivers/staging/xgifb/XGI_main_26.c
  drivers/staging/xgifb/vb_init.c

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>