x86/64: enable Hyper-V support in the x86_64 kernel config

Enabled Hyper-V network interface card driver, display adapter driver,
storage driver, keyboard driver, mouse driver and Hyper-V utility and
EFI boot support in the kernel for subtarget x86/64.
Convert the img file to vhd by Ubuntu qemu-img, rather than by the buildroot's
built-in qemu-img.

Tested on Windows Server 2008 r2 and 2012 r2 Gen1 and Gen2 VMs.

Signed-off-by: Tedaz <tedaz99999@hotmail.com>