watchdog: wdat_wdt: Fix ACPI table leak in probe function
wdat_wdt_probe() calls acpi_get_table() to obtain the WDAT ACPI table but
never calls acpi_put_table() on any paths. This causes a permanent ACPI
table memory leak.
Add a single cleanup path which calls acpi_put_table() to ensure
the ACPI table is always released.