Fix build break when freezer not configured

fs/cifs/transport.c: In function 'wait_for_response':
fs/cifs/transport.c:328: error: implicit declaration of function 'wait_event_freezekillable'

Caused by commit f06ac72e ("cifs, freezer: add
wait_event_freezekillable and have cifs use it").  In this config,
CONFIG_FREEZER is not set.
Reviewed-by: Shirish Pargaonkar <shirishp@us.ibm.com>
CC: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

include/linux/freezer.h

@@ -203,6 +203,9 @@ static inline void set_freezable_with_signal(void) {}
 #define wait_event_freezable_timeout(wq, condition, timeout)		\
 		wait_event_interruptible_timeout(wq, condition, timeout)
 
+#define wait_event_freezekillable(wq, condition)		\
+		wait_event_killable(wq, condition)
+
 #endif /* !CONFIG_FREEZER */
 
 #endif	/* FREEZER_H_INCLUDED */