watchdog: it87_wdt: Add support for IT8728F watchdog.

This works the same way IT8721F works, but it supports WDT_PWROK
(checked on the datasheet).

Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.eu>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 0542314..66e77ad 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -596,7 +596,12 @@
 	depends on X86 && EXPERIMENTAL
 	---help---
 	  This is the driver for the hardware watchdog on the ITE IT8702,
-	  IT8712, IT8716, IT8718, IT8720, IT8721, IT8726 Super I/O chips.
+	  IT8712, IT8716, IT8718, IT8720, IT8721, IT8726 and IT8728
+	  Super I/O chips.
+
+	  If the driver does not work, then make sure that the game port in
+	  the BIOS is enabled.
+
 	  This watchdog simply watches your kernel to make sure it doesn't
 	  freeze, and if it does, it reboots your computer after a certain
 	  amount of time.