linux-user: Fake /proc/cpuinfo

linux-user: Fake /proc/cpuinfo

Fedora 17 for ARM reads /proc/cpuinfo and fails if it doesn't contain
ARM related contents. This patch implements a quick hack to expose real
/proc/cpuinfo data taken from a real world machine.

The real fix would be to generate at least the flags automatically based
on the selected CPU. Please do not submit this patch upstream until this
has happened.

Signed-off-by: Alexander Graf <agraf@suse.de>
[AF: Rebased for v1.6 and v1.7]
Signed-off-by: Andreas Färber <afaerber@suse.de>