Watchdog: DA9052/53 PMIC watchdog support

This driver adds support for the watchdog functionality provided by
the Dialog Semiconductor DA9052 PMIC chip.

Tested on samsung smdkv6410 and i.mx53 QS boards.

Signed-off-by: Anthony Olech <Anthony.Olech@diasemi.com>
Signed-off-by: Ashish Jangam <ashish.jangam@kpitcummins.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>