qemu: Add patch to fix qemux86-64 EDSCA key problems
Without this patch, x86_64 images would show invalid EDSCA key errors
with sshd from openssh (but not dropbear) during init.
This would cause problems with operation with some distros where EDSCA
keys were mandatory. The issue was present in qemu 2.2.1 and not in
2.3.0-rc0, bisected to this commit which was then backported. This fixes
intermittent failures on the autobuilder. Issue is not present when
using KVM (consistent with a fault in TCG).
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
