ARM: dts: imx6: phycore-som: explicit disable pmic watchdog during suspend

ARM: dts: imx6: phycore-som: explicit disable pmic watchdog during suspend

By default the phycore-som has support for two watchdog devices: 1st the
internal imx6 watchdog and 2nd the DA9062 PMIC watchdog. According [1]
the PMIC watchdog is used as boot watchdog. It is common to use this
watchdog during "system up" time too. Furthermore the PMIC watchdog can
be used to address ERR007117 since the phycore-som can be equipped with
NAND or eMMC storage.

The PMIC watchdog can be enabled/disabled by the PMIC itself if the PMIC
enters POWERDOWN mode or by the host. The PMIC powerdown mode can't be
used due to the PCB design. So the watchdog is still enabled during a
suspend which causes a system reset. We need to tell the driver to
disable the watchdog during a system suspend and to reenable it upon a
resume to fix this.

[1] https://git.pengutronix.de/cgit/barebox/tree/arch/arm/dts/imx6qdl-phytec-phycore-som.dtsi#n73

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>