btrfs: pass the btrfs_bio_ctrl to submit_one_bio

submit_one_bio always works on the bio and compression flags from a
btrfs_bio_ctrl structure.  Pass the explicitly and clean up the
calling conventions by handling a NULL bio in submit_one_bio, and
using the btrfs_bio_ctrl to pass the mirror number as well.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>