SUNRPC: Shrink size of struct rpc_task

Move the field 'tk_rpc_status' so that we eliminate a 4 byte hole in the
structure.
For x86_64, this shrinks the size of the struct by 8 bytes.

'pahole' output before the change:
        /* size: 232, cachelines: 4, members: 27 */
        /* sum members: 222, holes: 1, sum holes: 4 */
        /* sum bitfield members: 8 bits (1 bytes) */
        /* padding: 5 */
        /* last cacheline: 40 bytes */

'pahole' output after the change:
        /* size: 224, cachelines: 4, members: 27 */
        /* padding: 1 */
        /* last cacheline: 32 bytes */
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

include/linux/sunrpc/sched.h

@@ -61,8 +61,6 @@ struct rpc_task {
 		struct rpc_wait		tk_wait;	/* RPC wait */
 	} u;
 
-	int			tk_rpc_status;	/* Result of last RPC operation */
-
 	/*
 	 * RPC call state
 	 */
@@ -82,6 +80,8 @@ struct rpc_task {
 	ktime_t			tk_start;	/* RPC task init timestamp */
 
 	pid_t			tk_owner;	/* Process id for batching tasks */
+
+	int			tk_rpc_status;	/* Result of last RPC operation */
 	unsigned short		tk_flags;	/* misc flags */
 	unsigned short		tk_timeouts;	/* maj timeouts */