cryptfs: improve logging of dm-crypt device creation

Log the main configuration of the dm-crypt device -- the name, the
cipher, the keysize, the real device, and the length -- in addition to
the extra parameters which we were already logging.

(We can't simply log the actual string passed to the kernel, of course,
 because that includes the key.  So we choose the fields individually.)

Test: booted device configured to use FDE and checked the log message
Change-Id: Ia95de807c4fad68d93b7e7e73508a01e5139dc76
1 file changed