dt-bindings: watchdog: apple,wdt: Add t8122 compatible

dt-bindings: watchdog: apple,wdt: Add t8122 compatible

The watchdog on the Apple silicon t8122 (M3) SoC is compatible with the
existing driver. Add "apple,t8122-wdt" as SoC specific compatible under
"apple,t8103-wdt" used by the driver.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Joshua Peisach <jpeisach@ubuntu.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Janne Grunau <j@jannau.net>
Link: https://lore.kernel.org/r/20260507-apple-m3-initial-devicetrees-v3-2-ca07c81b5dc7@jannau.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>