block/blk-throttle.c: fix return of 0/1 with return type bool

Fix 4 coccinelle warnings.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 680a0cc..9353b46 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -744,7 +744,7 @@
 static bool throtl_slice_used(struct throtl_grp *tg, bool rw)
 {
 	if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw]))
-		return 0;
+		return false;
 
 	return 1;
 }
@@ -842,7 +842,7 @@
 	if (tg->io_disp[rw] + 1 <= io_allowed) {
 		if (wait)
 			*wait = 0;
-		return 1;
+		return true;
 	}
 
 	/* Calc approx time to dispatch */
@@ -880,7 +880,7 @@
 	if (tg->bytes_disp[rw] + bio->bi_iter.bi_size <= bytes_allowed) {
 		if (wait)
 			*wait = 0;
-		return 1;
+		return true;
 	}
 
 	/* Calc approx time to dispatch */
@@ -923,7 +923,7 @@
 	if (tg->bps[rw] == -1 && tg->iops[rw] == -1) {
 		if (wait)
 			*wait = 0;
-		return 1;
+		return true;
 	}
 
 	/*