watchdog: Add Xilinx watchdog timer driver

Watchdog timer device driver for Xilinx xps_timebase_wdt compatible ip cores.
It takes watchdog timer configuration from device tree and it needs that its
parent has defined the property "clock-frecuency".
It is compatible with watchdog timer kernel API, so user apps like watchdogd
may talk with it.

Signed-off-by: Alejandro Cabrera <aldaya@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index df6b8ff..0635e72 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -888,6 +888,20 @@
 	  To compile this driver as a module, choose M here: the
 	  module will be called m54xx_wdt.
 
+# MicroBlaze Architecture
+
+config XILINX_WATCHDOG
+	tristate "Xilinx Watchdog timer"
+	depends on MICROBLAZE
+	---help---
+	  Watchdog driver for the xps_timebase_wdt ip core.
+
+	  IMPORTANT: The xps_timebase_wdt parent must have the property
+	  "clock-frequency" at device tree.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called of_xilinx_wdt.
+
 # MIPS Architecture
 
 config ATH79_WDT