[yocto] Add extra parameters for qemu script

[Ke, Liping]

> I tend to feel that this approach is more flexible, and scales better
> > than having to support each and every qemu option with our own script
> > syntax. Is this acceptable, or should we continue to support our own
> > custom options in addition to Criping's new approach?
> 
> My gut feeling is that having some simplified way to trigger possibly
> complex option combinations is still desirable but adding a way to pass
> additional custom commandline is equally good. This gives us the
> maximum
> flexibility moving forwards but keeps the script easy to use?
> 

Hi, Scott

So the conclusion is that I should keep the old (serial nographic) option while
adding the new "<-XXX -XXX -XXX>" option?
OK. I will send out the modified patch to you for review later.

Thanks& Regards,
criping


> Cheers,
> 
> Richard