imx6_spl: Add u-boot-dtb.img for SPL payload

Add u-boot-dtb.img for SPL_FS_LOAD_PAYLOAD_NAME when
OF_CONTROL used.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>

include/configs/imx6_spl.h

@@ -49,7 +49,11 @@
 
 /* Define the payload for FAT/EXT support */
 #if defined(CONFIG_SPL_FAT_SUPPORT) || defined(CONFIG_SPL_EXT_SUPPORT)
-#define CONFIG_SPL_FS_LOAD_PAYLOAD_NAME  "u-boot.img"
+# ifdef CONFIG_OF_CONTROL
+#  define CONFIG_SPL_FS_LOAD_PAYLOAD_NAME	"u-boot-dtb.img"
+# else
+#  define CONFIG_SPL_FS_LOAD_PAYLOAD_NAME	"u-boot.img"
+# endif
 #endif
 
 #if defined(CONFIG_MX6SX) || defined(CONFIG_MX6UL) || defined(CONFIG_MX6SL)