riscv: ax25-ae350: add SPL configuration

This patch provides four configurations which can support U-Boot SPL
to boot from RAM or FLASH and then boot FIT image including OpenSBI
FW_DYNAMIC firmware and U-Boot proper images from RAM or MMC boot devices.

With ae350_rv[32|64]_spl_defconfigs:

U-Boot SPL will be loaded by gdb or FSBL and runs in RAM in machine mode
and then load FIT image from RAM device on AE350.

With ae350_rv[32|64]_spl_xip_defconfigs:

U-Boot SPL can be burned into SPI flash and run in flash in machine mode
and then load FIT image from SPI flash or MMC device on AE350.

Signed-off-by: Rick Chen <rick@andestech.com>
Cc: KC Lin <kclin@andestech.com>
Cc: Alan Kao <alankao@andestech.com>
diff --git a/board/AndesTech/ax25-ae350/ax25-ae350.c b/board/AndesTech/ax25-ae350/ax25-ae350.c
index b43eebb..b0164a9 100644
--- a/board/AndesTech/ax25-ae350/ax25-ae350.c
+++ b/board/AndesTech/ax25-ae350/ax25-ae350.c
@@ -12,6 +12,7 @@
 #include <faraday/ftsmc020.h>
 #include <fdtdec.h>
 #include <dm.h>
+#include <spl.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -110,3 +111,29 @@
 	return 0;
 }
 #endif
+
+#ifdef CONFIG_SPL
+void board_boot_order(u32 *spl_boot_list)
+{
+	u8 i;
+	u32 boot_devices[] = {
+#ifdef CONFIG_SPL_RAM_SUPPORT
+		BOOT_DEVICE_RAM,
+#endif
+#ifdef CONFIG_SPL_MMC_SUPPORT
+		BOOT_DEVICE_MMC1,
+#endif
+	};
+
+	for (i = 0; i < ARRAY_SIZE(boot_devices); i++)
+		spl_boot_list[i] = boot_devices[i];
+}
+#endif
+
+#ifdef CONFIG_SPL_LOAD_FIT
+int board_fit_config_name_match(const char *name)
+{
+	/* boot using first FIT config */
+	return 0;
+}
+#endif