staging: xgifb: remove extra braces from if stmt (single branch)

Remove braces from one branch of if statement where both branches only
have a single line of code, as suggested in Documentation/CodingStyle

Signed-off-by: Nicholas Sim <nicholassimws@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>