qemu/arm-vexpress: add new sample config

Run the emulation with:

  qemu-system-arm -M vexpress-a9 -kernel output/images/zImage -drive file=output/images/rootfs.ext2,if=sd -append "console=ttyAMA0,115200 root=/dev/mmcblk0" -serial stdio -net nic,model=lan9118 -net user

The login prompt will appear in the terminal that started Qemu. The

graphical window is the framebuffer.

# Architecture

BR2_arm=y

BR2_cortex_a9=y

# system

BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_MDEV=y

BR2_TARGET_GENERIC_GETTY=y

BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"

# filesystem

BR2_TARGET_ROOTFS_EXT2=y

# BR2_TARGET_ROOTFS_TAR is not set

# Lock to 3.3 headers to avoid breaking with newer kernels

BR2_KERNEL_HEADERS_3_3=y

# Kernel

BR2_LINUX_KERNEL=y

BR2_LINUX_KERNEL_CUSTOM_VERSION=y

BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="3.3.4"

BR2_LINUX_KERNEL_DEFCONFIG="vexpress"

BR2_LINUX_KERNEL_ZIMAGE=y