SUNRPC: Inline xdr_commit_encode

Micro-optimization: For xdr_commit_encode call sites in
net/sunrpc/xdr.c, eliminate the extra calling sequence.  On my
client, this change saves about a microsecond for every 30 calls
to xdr_reserve_space().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xdr.c

@@ -560,7 +560,7 @@ EXPORT_SYMBOL_GPL(xdr_init_encode);
  * required at the end of encoding, or any other time when the xdr_buf
  * data might be read.
  */
-void xdr_commit_encode(struct xdr_stream *xdr)
+inline void xdr_commit_encode(struct xdr_stream *xdr)
 {
 	int shift = xdr->scratch.iov_len;
 	void *page;