sunrpc: use the struct net as the svc proc private

sunrpc: use the struct net as the svc proc private

commit 418b9687dece5bd763c09b5c27a801a7e3387be9 upstream.

nfsd is the only thing using this helper, and it doesn't use the private
currently.  When we switch to per-network namespace stats we will need
the struct net * in order to get to the nfsd_net.  Use the net as the
proc private so we can utilize this when we make the switch over.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>