riscv: Setup reserved-memory node for FU540

FU540 uses OF_SEPARATE instead of OF_PRIOR_STAGE.

Enable OF_BOARD_FIXUP to update the DT with reserved-memory node.
Signed-off-by: NAtish Patra <atish.patra@wdc.com>
Reviewed-by: NBin Meng <bmeng.cn@gmail.com>
Tested-by: NBin Meng <bmeng.cn@gmail.com>

arch/riscv/lib/fdt_fixup.c

@@ -100,3 +100,18 @@ int riscv_board_reserved_mem_fixup(void *fdt)
 
 	return 0;
 }
+
+#ifdef CONFIG_OF_BOARD_FIXUP
+int board_fix_fdt(void *fdt)
+{
+	int err;
+
+	err = riscv_board_reserved_mem_fixup(fdt);
+	if (err < 0) {
+		printf("failed to fixup DT for reserved memory: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+#endif

configs/sifive_fu540_defconfig

@@ -9,6 +9,7 @@ CONFIG_FIT=y
 CONFIG_MISC_INIT_R=y
 CONFIG_DISPLAY_CPUINFO=y
 CONFIG_DISPLAY_BOARDINFO=y
+CONFIG_OF_BOARD_FIXUP=y
 CONFIG_DEFAULT_DEVICE_TREE="hifive-unleashed-a00"
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_DM_MTD=y