[PATCH] knfsd: svcrpc: Simplify nfsd rpcsec_gss integrity code

Pull out some of the integrity code into its own function, otherwise
svcauth_gss_release() is going to become very ungainly after the addition of
privacy code.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>