qemu/configs: enable DRM+QXL for x86 and x86_64

Allows for nicer framebuffer emulation under Qemu with the QXL xorg
driver.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>