x86: Enable display for QEMU 64-bit

x86: Enable display for QEMU 64-bit

Enable the various options needed for display to work on the qemu-x86_64
board. This includes expanding the available malloc() memory in SPL,
since the PCI bus must be enumerated in order to find the video device.

It also includes enabling a bloblist, so that the video parameters can be
passed. This is placed at address 10000 but is not needed after U-Boot
proper reads the information there.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>