Fix cirrus drm driver for qemu use

From: Martin Koegler
Date: Tue Dec 24 2013 - 04:56:55 EST

On openSuSE, Xorg start fails, if modeset is enabled (

This is caused by the fact, that the fbhwdev part in Xorg uses smem_start/len of the "fix" part, which is
not initialized by the the cirrus drm driver.

The attached patch fixes this problem. I can't spot such a initialisation in HEAD,
so I forward this patch.