fscrypt: document testing with xfstests

Document how to test ext4, f2fs, and ubifs encryption with xfstests.

Change-Id: I5718b58b0a8f459e9866b0374d2ff63cc9ef0a1b
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
1 file changed