verdin-imx8mm: automatic ram size detection

Implement board_phys_sdram_size() to automatically detect Verdin iMX8M
Mini DualLite 1GB vs. Verdin iMX8M Mini Quad 2GB.

Note: This only works if we keep using similar RAM chips!
Signed-off-by: NMarcel Ziswiler <marcel.ziswiler@toradex.com>
Acked-by: NOleksandr Suvorov <oleksandr.suvorov@toradex.com>

board/toradex/verdin-imx8mm/verdin-imx8mm.c

@@ -180,6 +180,16 @@ int board_late_init(void)
 	return 0;
 }
 
+int board_phys_sdram_size(phys_size_t *size)
+{
+	if (!size)
+		return -EINVAL;
+
+	*size = get_ram_size((void *)PHYS_SDRAM, PHYS_SDRAM_SIZE);
+
+	return 0;
+}
+
 #if defined(CONFIG_OF_LIBFDT) && defined(CONFIG_OF_BOARD_SETUP)
 int ft_board_setup(void *blob, struct bd_info *bd)
 {