watchdog: starfive: Check pm_runtime_enabled() before decrementing usage counter

In the probe function, pm_runtime_put_sync() will fail on platform with
runtime PM disabled.
Check if runtime PM is enabled before calling pm_runtime_put_sync() to
fix it.

Fixes: db728ea9 ("drivers: watchdog: Add StarFive Watchdog driver")
Signed-off-by: Xingyu Wu <xingyu.wu@starfivetech.com>
Signed-off-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
Signed-off-by: Ji Sheng Teoh <jisheng.teoh@starfivetech.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240119082722.1133024-1-jisheng.teoh@starfivetech.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>