watchdog: davinci: reuse driver for keystone arch

The keystone arch uses the same IP watchdog, so add "ti,keystone-wdt"
compatible and correct identity.

The Keystone arch is using clocks in DT and source clock for watchdog
has to be specified, so add this to binding.

Signed-off-by: Ivan Khoronzhuk <[e-mail]>
Acked-by: Santosh Shilimkar <[e-mail]>
Reviewed-by: Guenter Roeck <[e-mail]>
Signed-off-by: Wim Van Sebroeck <[e-mail]>

Documentation/devicetree/bindings/watchdog/davinci-wdt.txt

···
-DaVinci Watchdog Timer (WDT) Controller
+Texas Instruments DaVinci/Keystone Watchdog Timer (WDT) Controller
 
 Required properties:
-- compatible : Should be "ti,davinci-wdt"
+- compatible : Should be "ti,davinci-wdt", "ti,keystone-wdt"
 - reg : Should contain WDT registers location and length
 
 Optional properties:
 - timeout-sec : Contains the watchdog timeout in seconds
+- clocks : the clock feeding the watchdog timer.
+	   Needed if platform uses clocks.
+	   See clock-bindings.txt
+
+Documentation:
+Davinci DM646x - http://www.ti.com/lit/ug/spruer5b/spruer5b.pdf
+Keystone - http://www.ti.com/lit/ug/sprugv5a/sprugv5a.pdf
 
 Examples:
 
···
 	compatible = "ti,davinci-wdt";
 	reg = <0x02320000 0x80>;
 	timeout-sec = <30>;
+	clocks = <&clkwdtimer0>;
 };

drivers/watchdog/Kconfig

···
 
 config DAVINCI_WATCHDOG
 	tristate "DaVinci watchdog"
-	depends on ARCH_DAVINCI
+	depends on ARCH_DAVINCI || ARCH_KEYSTONE
 	select WATCHDOG_CORE
 	help
 	  Say Y here if to include support for the watchdog timer
-	  in the DaVinci DM644x/DM646x processors.
+	  in the DaVinci DM644x/DM646x or Keystone processors.
 	  To compile this driver as a module, choose M here: the
 	  module will be called davinci_wdt.
 

drivers/watchdog/davinci_wdt.c

···
 
 static const struct watchdog_info davinci_wdt_info = {
 	.options = WDIOF_KEEPALIVEPING,
-	.identity = "DaVinci Watchdog",
+	.identity = "DaVinci/Keystone Watchdog",
 };
 
 static const struct watchdog_ops davinci_wdt_ops = {