riscv: configs: AE350 will use CONFIG_OF_SEPARATE when boots from flash

When AE350 boots from flash, use CONFIG_OF_SEPARATE instead of
CONFIG_OF_BOARD.

Also remove unused code about prior_stage_fdt_address.
And modify CONFIG_SYS_FDT_BASE as flash address.

Signed-off-by: Rick Chen <rick@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
diff --git a/board/AndesTech/ax25-ae350/ax25-ae350.c b/board/AndesTech/ax25-ae350/ax25-ae350.c
index d343453..3d65ce7 100644
--- a/board/AndesTech/ax25-ae350/ax25-ae350.c
+++ b/board/AndesTech/ax25-ae350/ax25-ae350.c
@@ -67,10 +67,6 @@
 
 void *board_fdt_blob_setup(void)
 {
-	void **ptr = (void *)&prior_stage_fdt_address;
-	if (fdt_magic(*ptr) == FDT_MAGIC)
-			return (void *)*ptr;
-
 	return (void *)CONFIG_SYS_FDT_BASE;
 }
 
diff --git a/configs/ae350_rv32_xip_defconfig b/configs/ae350_rv32_xip_defconfig
index 76534f2..07f1ecc 100644
--- a/configs/ae350_rv32_xip_defconfig
+++ b/configs/ae350_rv32_xip_defconfig
@@ -15,7 +15,7 @@
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_BOOTP_PREFER_SERVERIP=y
 CONFIG_CMD_CACHE=y
-CONFIG_OF_BOARD=y
+CONFIG_OF_SEPARATE=y
 CONFIG_DEFAULT_DEVICE_TREE="ae350_32"
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_NET_RANDOM_ETHADDR=y
diff --git a/configs/ae350_rv64_xip_defconfig b/configs/ae350_rv64_xip_defconfig
index f7f2925..28afd81 100644
--- a/configs/ae350_rv64_xip_defconfig
+++ b/configs/ae350_rv64_xip_defconfig
@@ -16,7 +16,7 @@
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_BOOTP_PREFER_SERVERIP=y
 CONFIG_CMD_CACHE=y
-CONFIG_OF_BOARD=y
+CONFIG_OF_SEPARATE=y
 CONFIG_DEFAULT_DEVICE_TREE="ae350_64"
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_NET_RANDOM_ETHADDR=y
diff --git a/include/configs/ax25-ae350.h b/include/configs/ax25-ae350.h
index 395f3a4..a4037f3 100644
--- a/include/configs/ax25-ae350.h
+++ b/include/configs/ax25-ae350.h
@@ -40,7 +40,7 @@
 #define CONFIG_SYS_MALLOC_LEN   (512 << 10)
 
 /* DT blob (fdt) address */
-#define CONFIG_SYS_FDT_BASE		0x000f0000
+#define CONFIG_SYS_FDT_BASE		0x800f0000
 
 /*
  * Physical Memory Map