It turns out (as will be clear from follow-up patches)
we do not really need any kvm para macros host side
for now, except on x86, and there we need it
unconditionally whether we run on kvm or we don't.

Import the x86 asm/kvm_para.h into standard-headers,
follow-up patches remove a bunch of code using this.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>