loop: simplify code of LOOP_SET_FD failure

function                                             old     new   delta
set_loop                                             790     760     -30

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/libbb/loop.c b/libbb/loop.c
index 8e5c915..256b7ac 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -188,13 +188,9 @@
 		/* If device is free, try to claim it */
 		if (rc && errno == ENXIO) {
 			/* Associate free loop device with file */
-			if (ioctl(lfd, LOOP_SET_FD, ffd)) {
-				/* Ouch. Are we racing with other mount? */
-				if (!*device) {
-					close(lfd);
-//TODO: add "if (--failcount != 0) ..."?
-					continue;
-				}
+			rc = ioctl(lfd, LOOP_SET_FD, ffd);
+			if (rc != 0) {
+				/* Ouch... race: the device already has a fd */
 				goto close_and_try_next_loopN;
 			}
 			memset(&loopinfo, 0, sizeof(loopinfo));