btrfs: remove unused parameter fs_devices from btrfs_init_workqueues

Since commit ba8a9d0795 ("Btrfs: delete the entire async bio submission
framework") removed submit workqueues, the parameter fs_devices is not used
anymore.

Remove it, no functional changes.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Su Yue <l@damenly.su>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -2291,8 +2291,7 @@ static void btrfs_init_qgroup(struct btrfs_fs_info *fs_info)
 	mutex_init(&fs_info->qgroup_rescan_lock);
 }
 
-static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info,
-		struct btrfs_fs_devices *fs_devices)
+static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info)
 {
 	u32 max_active = fs_info->thread_pool_size;
 	unsigned int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
@@ -3423,7 +3422,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 		fs_info->subpage_info = subpage_info;
 	}
 
-	ret = btrfs_init_workqueues(fs_info, fs_devices);
+	ret = btrfs_init_workqueues(fs_info);
 	if (ret) {
 		err = ret;
 		goto fail_sb_buffer;