SUNRPC: sunrpc should not explicitly depend on NFS config options

Change explicit references to CONFIG_NFS_V4_1 to implicit ones
Get rid of the unnecessary defines in backchannel_rqst.c and
bc_svc.c: the Makefile takes care of those dependency.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/svc.h

@@ -92,7 +92,7 @@ struct svc_serv {
 	struct module *		sv_module;	/* optional module to count when
 						 * adding threads */
 	svc_thread_fn		sv_function;	/* main function for threads */
-#if defined(CONFIG_NFS_V4_1)
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 	struct list_head	sv_cb_list;	/* queue for callback requests
 						 * that arrive over the same
 						 * connection */
@@ -100,7 +100,7 @@ struct svc_serv {
 	wait_queue_head_t	sv_cb_waitq;	/* sleep here if there are no
 						 * entries in the svc_cb_list */
 	struct svc_xprt		*sv_bc_xprt;	/* callback on fore channel */
-#endif /* CONFIG_NFS_V4_1 */
+#endif /* CONFIG_SUNRPC_BACKCHANNEL */
 };
 
 /*