The dev_max constraints are defined in the raid_attr table, use it
instead of open-coding it.
Signed-off-by: David Sterba <dsterba@suse.com>
 {
        u64 num_dev;
 
-       if (type & (BTRFS_BLOCK_GROUP_RAID10 |
-                   BTRFS_BLOCK_GROUP_RAID0 |
-                   BTRFS_BLOCK_GROUP_RAID5 |
-                   BTRFS_BLOCK_GROUP_RAID6))
+       num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
+       if (!num_dev)
                num_dev = fs_info->fs_devices->rw_devices;
-       else if (type & BTRFS_BLOCK_GROUP_RAID1)
-               num_dev = 2;
-       else
-               num_dev = 1;    /* DUP or single */
 
        return num_dev;
 }