[DUMMY]: Avoid an oops when dummy_init_one() failed

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c
index 36d5117..2146cf7 100644
--- a/drivers/net/dummy.c
+++ b/drivers/net/dummy.c
@@ -132,6 +132,7 @@
 	for (i = 0; i < numdummies && !err; i++)
 		err = dummy_init_one(i); 
 	if (err) { 
+		i--;
 		while (--i >= 0)
 			dummy_free_one(i);
 	}