imx_watchdog: Add a header file for watchdog registers

Create fsl_wdog.h to store the watchdog registers and bit fields.

This can be useful when accesses to the watchdog block are made from other
parts, such as arch/arm/ cpu code.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
diff --git a/drivers/watchdog/imx_watchdog.c b/drivers/watchdog/imx_watchdog.c
index 9a77a54..0d77595 100644
--- a/drivers/watchdog/imx_watchdog.c
+++ b/drivers/watchdog/imx_watchdog.c
@@ -8,19 +8,7 @@
 #include <asm/io.h>
 #include <watchdog.h>
 #include <asm/arch/imx-regs.h>
-
-struct watchdog_regs {
-	u16	wcr;	/* Control */
-	u16	wsr;	/* Service */
-	u16	wrsr;	/* Reset Status */
-};
-
-#define WCR_WDZST	0x01
-#define WCR_WDBG	0x02
-#define WCR_WDE		0x04	/* WDOG enable */
-#define WCR_WDT		0x08
-#define WCR_SRS		0x10
-#define SET_WCR_WT(x)	(x << 8)
+#include <fsl_wdog.h>
 
 #ifdef CONFIG_IMX_WATCHDOG
 void hw_watchdog_reset(void)