fs: ocfs: remove unnecessary assertion in dlm_migrate_lockres

In the only caller of dlm_migrate_lockres() - dlm_empty_lockres(),
target is checked for O2NM_MAX_NODES.  Thus, the assertion in
dlm_migrate_lockres() is unnecessary and can be removed.  The patch
eliminates such a check.

Link: http://lkml.kernel.org/r/20191218194111.26041-1-pakki001@umn.edu
Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>