nfsd: factor out hash functions for export caches.

Both the _lookup and the _update functions for these two caches
independently calculate the hash of the key.
So factor out that code for improved reuse.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
1 file changed