Please strip default cmdline

Hi

When starting the vexpress kernel under QEMU with no -append or an empty -append argument, the kernel falls back to the configured default cmdline:
[ 0.000000] Kernel command line: root=/dev/nfs nfsroot=10.1.69.3:/work/nfsroot ip=dhcp console=ttyAMA0 mem=128M

this specific line is hurtful in multiple ways:
* depends on the network when it might not be available; this hardcoded IP address looks really dangerous
* forces console=ttyAMA0 when framebuffer might be available (tty1 or tty0 alias)
* limits RAM to 128M while 1024M might be available

I think none of this should be in the default kernel cmdline, at least not in the Ubuntu binaries.

Would you mind stripping them off the config?

Thanks!