Staging: xgifb: Fixed a code-style warning

Added a blank line after declarations to fix the following warning issued by checkpatch.pl:

drivers/staging/xgifb/vb_init.c:800: WARNING: Missing a blank line after declarations

Signed-off-by: Chaitanya Hazarey <c@24.io>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>