[PATCH] Nitpick: fix compilation for newer kernels

[Zach Brown]

> crfs is failing to build in early enough kernels due to some changes
> to the VM. I'm assuming you're tracking the latest, and are not willing to
> maintain lots of compatibility code conditional on the kernel version, so
> I'm just sending a definitive fix for it.
> 
> Let me know if it's acceptable.

I finally moved my target kernel forward and applied your fixes after
tweaking the commit message a little.  Thanks for sending it in.

- z