hw/arm/virt: Silence dtc /memory warning

hw/arm/virt: Silence dtc /memory warning

When running dtc on the guest /proc/device-tree we get the
following warning: Warning (unit_address_vs_reg): Node /memory
has a reg or ranges property, but no unit name".

Let's fix that by adding the unit address to the node name. We also
don't create the /memory node anymore in create_fdt(). We directly
create it in load_dtb. /chosen still needs to be created in create_fdt
as the uart needs it. In case the user provided his own dtb, we nop
all memory nodes found in root and create new one(s).

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Message-id: 1530044492-24921-4-git-send-email-eric.auger@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>