nfsd: clean up svc_reserve_auth()

This is a void function attempting to return the return value from
another void function, which seems harmless but extremely weird, and
apparently makes some compilers complain.

While we're there, clean up a little (e.g. the switch statement had a
minor style problem and seemed overkill as long as there's only one
case).

Thanks to Trond for noticing this.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/svc.h

@@ -409,16 +409,13 @@ char *		   svc_print_addr(struct svc_rqst *, char *, size_t);
  * for all cases without actually generating the checksum, so we just use a
  * static value.
  */
-static inline void
-svc_reserve_auth(struct svc_rqst *rqstp, int space)
+static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space)
 {
 	int added_space = 0;
 
-	switch(rqstp->rq_authop->flavour) {
-		case RPC_AUTH_GSS:
+	if (rqstp->rq_authop->flavour)
 		added_space = RPC_MAX_AUTH_SIZE;
-	}
-	return svc_reserve(rqstp, space + added_space);
+	svc_reserve(rqstp, space + added_space);
 }
 
 #endif /* SUNRPC_SVC_H */