x86: zimage: Support booting Linux kernel from an EFI payload

x86: zimage: Support booting Linux kernel from an EFI payload

At present Linux kernel loaded from U-Boot as an EFI payload does
not boot. This fills in kernel's boot params structure with the
required critical EFI information like system table address and
memory map stuff so that kernel can obtain essential data like
runtime services and ACPI table to boot.

With this patch, now U-Boot as an EFI payload becomes much more
practical: it is another option of kernel bootloader, ie, can be
a replacement for grub.

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