ARM: imx6: DHCOM i.MX6 PDK: Enable sysreset driver and wdt command

The SPL does not have DM enabled and therefor still needs to use the
hardware watchdog interface provided by the imx-watchdog driver.

Fixes: broken reset command after f2929d11 ("watchdog: imx: Use
       immediate reset bits for expire_now")
Signed-off-by: NClaudius Heine <ch@denx.de>

configs/dh_imx6_defconfig

@@ -40,6 +40,7 @@ CONFIG_CMD_MMC=y
 CONFIG_CMD_SATA=y
 CONFIG_CMD_USB=y
 CONFIG_CMD_USB_MASS_STORAGE=y
+CONFIG_CMD_WDT=y
 CONFIG_CMD_CACHE=y
 CONFIG_CMD_TIME=y
 CONFIG_CMD_EXT4_WRITE=y
@@ -83,6 +84,8 @@ CONFIG_DM_SCSI=y
 CONFIG_SPI=y
 CONFIG_DM_SPI=y
 CONFIG_MXC_SPI=y
+CONFIG_SYSRESET=y
+CONFIG_SYSRESET_WATCHDOG=y
 CONFIG_USB=y
 CONFIG_DM_USB=y
 CONFIG_USB_GADGET=y

include/configs/dh_imx6.h

@@ -87,6 +87,11 @@
 #endif
 
 /* Watchdog */
+#if defined(CONFIG_SPL_BUILD)
+#undef CONFIG_WDT
+#undef CONFIG_WATCHDOG
+#define CONFIG_HW_WATCHDOG
+#endif
 
 /* allow to overwrite serial and ethaddr */
 #define CONFIG_ENV_OVERWRITE