Revert "isdn: mISDNinfineon: fix potential NULL pointer dereference"

Revert "isdn: mISDNinfineon: fix potential NULL pointer dereference"

This reverts commit 7fa727a920cc87e3d836cf324fe8dc8c851e5b3c.

Because of recent interactions with developers from @umn.edu, all
commits from them have been recently re-reviewed to ensure if they were
correct or not.

Upon review, this commit was found to be incorrect for the reasons
below, so it must be reverted.  It will be fixed up "correctly" in a
later kernel change.

The original commit was incorrect, it should have never have used
"unlikely()" and if it ever does trigger, resources are left grabbed.

Given there are no users for this code around, I'll just revert this and
leave it "as is" as the odds that ioremap() will ever fail here is
horrendiously low.

Cc: Kangjie Lu <kjlu@umn.edu>
Cc: David S. Miller <davem@davemloft.net>
Link: https://lore.kernel.org/r/20210503115736.2104747-41-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>