sunrpc: properly type pc_release callbacks

Drop the p and resp arguments as they are always NULL or can trivially
be derived from the rqstp argument.  With that all functions now have the
same prototype, and we can remove the unsafe casting to kxdrproc_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 8fda4ab..a158579d 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -743,7 +743,7 @@ extern __be32
 nfsd4_release_lockowner(struct svc_rqst *rqstp,
 		struct nfsd4_compound_state *,
 		struct nfsd4_release_lockowner *rlockowner);
-extern int nfsd4_release_compoundargs(void *rq, __be32 *p, void *resp);
+extern void nfsd4_release_compoundargs(struct svc_rqst *rqstp);
 extern __be32 nfsd4_delegreturn(struct svc_rqst *rqstp,
 		struct nfsd4_compound_state *, struct nfsd4_delegreturn *dr);
 extern __be32 nfsd4_renew(struct svc_rqst *rqstp,