mb/qemu-riscv: update to match current qemu version

Boots again to payload not found on qemu.

Change-Id: Ie107eb882cbaac5a5a06c1ff990e7b9364377640
Signed-off-by: Philipp Hug <philipp@hug.cx>
Reviewed-on: https://review.coreboot.org/c/30554
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/src/mainboard/emulation/qemu-riscv/mainboard.c b/src/mainboard/emulation/qemu-riscv/mainboard.c
index 7061bcf..4b428aa 100644
--- a/src/mainboard/emulation/qemu-riscv/mainboard.c
+++ b/src/mainboard/emulation/qemu-riscv/mainboard.c
@@ -16,6 +16,7 @@
 #include <console/console.h>
 #include <device/device.h>
 #include <cbmem.h>
+#include <symbols.h>
 
 static void mainboard_enable(struct device *dev)
 {
@@ -24,7 +25,7 @@
 		die("No dev0; die\n");
 	}
 
-	ram_resource(dev, 0, 2048, 32768);
+	ram_resource(dev, 0, (uintptr_t)_dram / KiB, CONFIG_DRAM_SIZE_MB * KiB);
 	cbmem_recovery(0);
 }