watchdog.h: Move hw_watchdog_init prototype to end, guard

In commit abbab70 we added a prototype for hw_watchdog_init, in a
Freescale i.MX watchdog driver.  We did not however guard it with an
__ASSEMBLY__ check and broke some platforms.  Move this to the end of
the file with other prototypes and guard it.

Signed-off-by: Tom Rini <trini@ti.com>

include/watchdog.h

@@ -35,7 +35,6 @@
  * Hardware watchdog
  */
 #ifdef CONFIG_HW_WATCHDOG
-	void hw_watchdog_init(void);
 	#if defined(__ASSEMBLY__)
 		#define WATCHDOG_RESET bl hw_watchdog_reset
 	#else
@@ -91,4 +90,8 @@
 	void reset_4xx_watchdog(void);
 #endif
 
+/* Freescale i.MX */
+#if defined(CONFIG_IMX_WATCHDOG) && !defined(__ASSEMBLY__)
+	void hw_watchdog_init(void);
+#endif
 #endif /* _WATCHDOG_H_ */