watchdog: it87_wdt: Add support for IT8721F watchdog

This patch adds support for a watchdog in IT8721F Super IO
chip to it87_wdt driver.
This new chips differ from the older IT87xxxF chips 
in the following ways:

* WDT_GAMEPORT is not in IT8721F.
* WDT_PWROK is not in IT8721F.

Signed-off-by: Haruo Tomita <haruo.tomita@toshiba.co.jp>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 322b36a..229a9c1 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -580,7 +580,7 @@
 	depends on X86 && EXPERIMENTAL
 	---help---
 	  This is the driver for the hardware watchdog on the ITE IT8702,
-	  IT8712, IT8716, IT8718, IT8720, IT8726, IT8712 Super I/O chips.
+	  IT8712, IT8716, IT8718, IT8720, IT8721, IT8726 Super I/O chips.
 	  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.