board/common: 192 MiB RAM is not longer enough, increase to 256 MiB

Regrettably, the latest additions of functionality to Infix have also
incresed the size of the ramdisk.  We expect it to go down slightly
before v1.0, but considering we'll add Frr before then it's better to
be realistic of our needs when run in GNS3.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

board/common/mkgns3a.sh

@@ -18,7 +18,7 @@ cat <<EOF >"$BINARIES_DIR/infix.gns3a"
     "qemu": {
         "adapter_type": "virtio-net-pci",
         "adapters": 10,
-        "ram": 192,
+        "ram": 256,
         "cpus": 1,
         "hda_disk_interface": "virtio",
         "arch": "x86_64",