zynq: Make CONFIG_OF_EMBED default case

Use embedded DTB to let users use u-boot instead of u-boot-dtb.bin.
And fix SPL to use this target.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/include/configs/zynq-common.h b/include/configs/zynq-common.h
index cc72c86..e7ab50a 100644
--- a/include/configs/zynq-common.h
+++ b/include/configs/zynq-common.h
@@ -319,7 +319,7 @@
 #define CONFIG_SYS_MMCSD_FS_BOOT_PARTITION     1
 #define CONFIG_SPL_LIBDISK_SUPPORT
 #define CONFIG_SPL_FAT_SUPPORT
-#define CONFIG_SPL_FS_LOAD_PAYLOAD_NAME     "u-boot-dtb.img"
+#define CONFIG_SPL_FS_LOAD_PAYLOAD_NAME     "u-boot.img"
 #endif
 
 /* Disable dcache for SPL just for sure */