riscv: ax25-ae350: Use generic memory size setup

To get memory size from device tree instead of
get_ram_size(). This can avoid memory access fault
in U-Boot proper after PMP configurations in OpenSBI.

Signed-off-by: Rick Chen <rick@andestech.com>
Cc: KC Lin <kclin@andestech.com>
Cc: Alan Kao <alankao@andestech.com>

board/AndesTech/ax25-ae350/ax25-ae350.c

@@ -30,29 +30,12 @@ int board_init(void)
 
 int dram_init(void)
 {
-	unsigned long sdram_base = PHYS_SDRAM_0;
-	unsigned long expected_size = PHYS_SDRAM_0_SIZE + PHYS_SDRAM_1_SIZE;
-	unsigned long actual_size;
-
-	actual_size = get_ram_size((void *)sdram_base, expected_size);
-	gd->ram_size = actual_size;
-
-	if (expected_size != actual_size) {
-		printf("Warning: Only %lu of %lu MiB SDRAM is working\n",
-			actual_size >> 20, expected_size >> 20);
-	}
-
-	return 0;
+	return fdtdec_setup_mem_size_base();
 }
 
 int dram_init_banksize(void)
 {
-	gd->bd->bi_dram[0].start = PHYS_SDRAM_0;
-	gd->bd->bi_dram[0].size =  PHYS_SDRAM_0_SIZE;
-	gd->bd->bi_dram[1].start = PHYS_SDRAM_1;
-	gd->bd->bi_dram[1].size =  PHYS_SDRAM_1_SIZE;
-
-	return 0;
+	return fdtdec_setup_memory_banksize();
 }
 
 #if defined(CONFIG_FTMAC100) && !defined(CONFIG_DM_ETH)