Staging: xgifb: Fixed lots of coding style issues.

There were hundreds of warnings, but now there's only four. These are
related to the 'volatile' keyword and printk(), which I think should be
left to the maintainers to modify if deemed necessary.

Signed-off-by: Daniel Kenji Toyama <kenji.toyama@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>