watchdog: loongson1_wdt: Add DT support

This patch adds the of_match_table to enable DT support
of Loongson-1 watchdog driver.
And modify the parameter of devm_clk_get_enabled() accordingly.

Signed-off-by: Keguang Zhang <keguang.zhang@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lkml.kernel.org/r/20230511121159.463645-3-keguang.zhang@gmail.com


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