watchdog: imx: add config to disable wdog reset

Add Kconfig option WATCHDOG_RESET_DISABLE to disable watchdog reset
in imx_watchdog driver, so that the watchdog will not be fed in
u-boot if CONFIG_WATCHDOG_RESET_DISABLE is enabled.

Signed-off-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
diff --git a/drivers/watchdog/imx_watchdog.c b/drivers/watchdog/imx_watchdog.c
index ddcf474..14cc618 100644
--- a/drivers/watchdog/imx_watchdog.c
+++ b/drivers/watchdog/imx_watchdog.c
@@ -16,10 +16,12 @@
 #ifdef CONFIG_IMX_WATCHDOG
 void hw_watchdog_reset(void)
 {
+#ifndef CONFIG_WATCHDOG_RESET_DISABLE
 	struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR;
 
 	writew(0x5555, &wdog->wsr);
 	writew(0xaaaa, &wdog->wsr);
+#endif /* CONFIG_WATCHDOG_RESET_DISABLE*/
 }
 
 void hw_watchdog_init(void)