staging: lustre: remove ll_mrf_ret

It's just 'void' and only used in one place, so just remove it, it's
useless.

Cc: Peng Tao <tao.peng@emc.com>
Cc: Zhao Hongjiang <zhaohongjiang@huawei.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/linux/lustre_compat25.h

@@ -232,7 +232,6 @@ static inline int ll_namei_to_lookup_intent_flag(int flag)
 	return flag;
 }
 
-# define ll_mrf_ret void
 # define LL_MRF_RETURN(rc)
 
 #include <linux/fs.h>

drivers/staging/lustre/lustre/llite/lloop.c

@@ -337,8 +337,7 @@ static unsigned int loop_get_bio(struct lloop_device *lo, struct bio **req)
 	return count;
 }
 
-static ll_mrf_ret
-loop_make_request(struct request_queue *q, struct bio *old_bio)
+static void loop_make_request(struct request_queue *q, struct bio *old_bio)
 {
 	struct lloop_device *lo = q->queuedata;
 	int rw = bio_rw(old_bio);