Merge branch 'isdn'

Tilman Schmidt says:

====================
Coverity patches for drivers/isdn

Here's a series of patches for the ISDN CAPI subsystem and the
Gigaset ISDN driver.
Patches 1 to 7 are specific fixes for Coverity warnings.
Patches 8 to 11 fix related problems with the handling of invalid
CAPI command codes I noticed while working on this.
Patch 12 fixes an unrelated problem I noticed during the subsequent
regression tests.
It would be great if these could still be merged.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>