watchdog: rzv2h_wdt: Discard pm_runtime_put() return value

Failing device probe due to pm_runtime_put() returning an error is not
particularly useful.

Returning an error code from pm_runtime_put() merely means that it has
not queued up a work item to check whether or not the device can be
suspended and there are many perfectly valid situations in which that
can happen, like after writing "on" to the devices' runtime PM "control"
attribute in sysfs for one example. It also happens when the kernel is
configured with CONFIG_PM unset.

Accordingly, update rzt2h_wdt_wdtdcr_init() to simply discard the return
value of pm_runtime_put() and return success to the caller after
invoking that function.

This will facilitate a planned change of the pm_runtime_put() return
type to void in the future.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://patch.msgid.link/1867890.VLH7GnMWUR@rafael.j.wysocki