x86/hyperv: provide percpu hypercall input page

x86/hyperv: provide percpu hypercall input page

Hyper-V's input / output argument must be 8 bytes aligned an not cross
page boundary. One way to satisfy those requirements is to use percpu
page.

For the foreseeable future we only need to provide input for TLB
and APIC hypercalls, so skip setting up an output page.

We will also need to provide an ap_setup hook for secondary cpus to
setup its own input page.

Signed-off-by: Wei Liu <liuwe@microsoft.com>
Reviewed-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>