MAINTAINERS: Add Apple watchdog to ARM/APPLE MACHINE SUPPORT

Add apple_wdt.c under the ARM/APPLE MACHINE SUPPORT entry.

Signed-off-by: Sven Peter <sven@svenpeter.dev>
Signed-off-by: Hector Martin <marcan@marcan.st>

MAINTAINERS

@@ -1760,6 +1760,7 @@ F:	drivers/irqchip/irq-apple-aic.c
 F:	drivers/mailbox/apple-mailbox.c
 F:	drivers/pinctrl/pinctrl-apple-gpio.c
 F:	drivers/soc/apple/*
+F:	drivers/watchdog/apple_wdt.c
 F:	include/dt-bindings/interrupt-controller/apple-aic.h
 F:	include/dt-bindings/pinctrl/apple.h
 F:	include/linux/apple-mailbox.h