fs: Convert unnamed_dev_ida to new API

The new API is much easier for this user.  Also add kerneldoc for
get_anon_bdev().

Signed-off-by: Matthew Wilcox <willy@infradead.org>
This commit is contained in:
Matthew Wilcox 2018-06-11 12:03:31 -04:00
commit 5a66847e44