[openwrt/openwrt] umbim: fix return value of proto_mbim_setup()

[LEDE Commits]

adrian pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/6bc4c0ae3eb3dff6e410b5b012ab0bec267adb5a

commit 6bc4c0ae3eb3dff6e410b5b012ab0bec267adb5a
Author: Adrian Schmutzler <freifunk at adrianschmutzler.de>
AuthorDate: Sat Jun 5 17:59:39 2021 +0200

    umbim: fix return value of proto_mbim_setup()
    
    The variable name appears to be mistyped.
    
    Suggested-by: Howard Chu <hyc at symas.com>
    Signed-off-by: Adrian Schmutzler <freifunk at adrianschmutzler.de>
---
 package/network/utils/umbim/files/lib/netifd/proto/mbim.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/network/utils/umbim/files/lib/netifd/proto/mbim.sh b/package/network/utils/umbim/files/lib/netifd/proto/mbim.sh
index 804870d7d4..abbabd6625 100755
--- a/package/network/utils/umbim/files/lib/netifd/proto/mbim.sh
+++ b/package/network/utils/umbim/files/lib/netifd/proto/mbim.sh
@@ -155,7 +155,7 @@ proto_mbim_setup() {
 		sleep 15
 	}
 
-	return $rt
+	return $ret
 }
 
 proto_mbim_teardown() {