regulator: pca9450: Enable system reset on WDOG_B assertion

By default the PCA9450 doesn't handle the assertion of the WDOG_B
signal, but this is required to guarantee that things like software
resets triggered by the watchdog work reliably.

As we don't want to rely on the bootloader to enable this, we tell
the PMIC to issue a cold reset in case the WDOG_B signal is
asserted (WDOG_B_CFG = 10), just as the NXP U-Boot code does.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Link: https://lore.kernel.org/r/20210211105534.38972-3-frieder.schrempf@kontron.de
Signed-off-by: Mark Brown <broonie@kernel.org>