dt-bindings: watchdog: aspeed,ast2400-wdt: Add support for AST2700

dt-bindings: watchdog: aspeed,ast2400-wdt: Add support for AST2700

Add support for the AST2700 SoC in the ASPEED watchdog device tree
bindings. This includes:

- Adding "aspeed,ast2700-wdt" to the compatible string list.
- Extending the "aspeed,reset-mask" property description for AST2700.
- Defining AST2700-specific reset mask bits in aspeed-wdt.h,
  covering RESET1 to RESET5.

Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>