btrfs: move btrfs_init_dev_replace_tgtdev to dev-replace.c and make static

The function logically belongs there and there's only a single caller,
no need to export it. No code changes.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
3 files changed