dm cache policy smq: move 'dm-cache-default' module alias to SMQ

When creating dm-cache with the default policy, it will call
request_module("dm-cache-default") to register the default policy.
But the "dm-cache-default" alias was left referring to the MQ policy.
Fix this by moving the module alias to SMQ.

Fixes: bccab6a0 (dm cache: switch the "default" cache replacement policy from mq to smq)
Signed-off-by: NYi Zhang <yizhan@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

drivers/md/dm-cache-policy-mq.c

@@ -1471,5 +1471,3 @@ module_exit(mq_exit);
 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("mq cache policy");
-
-MODULE_ALIAS("dm-cache-default");

drivers/md/dm-cache-policy-smq.c

@@ -1789,3 +1789,5 @@ module_exit(smq_exit);
 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("smq cache policy");
+
+MODULE_ALIAS("dm-cache-default");