ocfs2: Change mlog_bug_on to BUG_ON in ocfs2_lockid.h

The masklog code is in the o2cb stack, but ocfs2_lockid.h now needs to
be included by the user stack.  The BUG() in ocfs2_lock_type_string()
does not need masklog support, so change it to a regular BUG_ON().

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>