DM: WDT: Convert WDT driver to use DM/DTS (including SYSRESET)

This commit enables support for CONFIG_WDT in the U-Boot proper. Moreover,
the SYSRESET_WATCHDOG driver is used to support 'reset' command.

As SPL is not yet ready for DM conversion, the CONFIG_HW_WATCHDOG is
enabled for it. This allows the legacy SPL code to work properly.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
diff --git a/include/configs/display5.h b/include/configs/display5.h
index bbcb5da..de11ff6 100644
--- a/include/configs/display5.h
+++ b/include/configs/display5.h
@@ -342,7 +342,11 @@
 
 /* Watchdog */
 #define CONFIG_WATCHDOG_TIMEOUT_MSECS   15000
-
+#if defined(CONFIG_SPL_BUILD)
+#undef CONFIG_WDT
+#undef CONFIG_WATCHDOG
+#define CONFIG_HW_WATCHDOG
+#endif
 /* ENV config */
 #ifdef CONFIG_ENV_IS_IN_SPI_FLASH
 #define CONFIG_ENV_SIZE		(SZ_64K)