The existing limbdb is intended to work with GPIO pin with "mdb-wakeup-out"
name. But there is no such label in the existing device tree for
SantVend - mdbmaster_wakeup_out is used instead. Rename this label to make
available userspace tools work.

Signed-off-by: Mikhail Vanyulin <mikhail.vanyulin@rtsoft.de>