The bd70528 watchdog driver is probed by MFD driver. Add MODULE_ALIAS
in order to allow udev to load the module when MFD sub-device cell for
watchdog is added.

Fixes: bbc88a0e ("watchdog: bd70528: Initial support for ROHM BD70528 watchdog block")
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>