hwmon: (aspeed-g6-pwm-tach): Add AST2700 compatible string

Extends device tree support to include the AST2700 chip variant by
adding its compatible string to the device match table.

The AST2700 PWM/TACH hardware is compatible with the existing driver
implementation used for AST2600.

Signed-off-by: Billy Tsai <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Guenter Roeck <[e-mail]>

drivers/hwmon/aspeed-g6-pwm-tach.c

···
 	{
 		.compatible = "aspeed,ast2600-pwm-tach",
 	},
+	{
+		.compatible = "aspeed,ast2700-pwm-tach",
+	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, aspeed_pwm_tach_match);