VFS: C99 sparse format for struct vfsops

Gang,

My fingers have been itching to do this since the day phk_at_ planted this
idea in my brain (re: cdevsw initialisations).  Basically, it changes
the vfsops to use C99 sparse format, just like cdevsw.  It removes a lot
of junk default initialisations, and duplication.

Just like phk_at_ said in his mail for cdevsw; likewise, we wil be able to
add new vfsops without having to hunt down each driver to match.  Except
this patch was "not" generated automatically.

While there, I have also nuked all the prototypes for the vfsops, and
replaced them with the typedefs, available in sys/mount.h, i.e.
vfs_<op>_t.  If this patch gets approved by some senior mac-daddies of
FreeBSD, I can kindly ask my mentor, DES, to commit this for me. 8-)

The patch: http://people.FreeBSD.ORG/~hmp/patches/vfs-voodoo.patch

My mentor, and some other developers on secret IRC channel have given
this a cursory glance.  I am composing my email from a kernel running
with this patch -- no rabbits, or hard disks were harmed in the making
of this patch.

Cheers.

	-- Hiten (hmp_at_FreeBSD.ORG)