s390/mm: use VM_BUG_ON in crst_table_[upgrade|downgrade]

The BUG_ON in crst_table_[upgrade|downgrade] is a debugging aid,
replace it with VM_BUG_ON.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2017-08-31 13:18:22 +02:00
commit 2fc4876ea8