core: Remove support for ib700 watchdog

This watchdog is no longer supported as it is an ISA device.

Change-Id: I83242f3ccd7c2fc6ed7c4321ecaa89fca0140093
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1014531
Signed-off-by: Martin Sivak <msivak@redhat.com>