xen: x86 pvh: use XENMEM_add_to_physmap_range for foreign gmfn mappings

xen: x86 pvh: use XENMEM_add_to_physmap_range for foreign gmfn mappings

Squeezing the necessary fields into the existing XENMEM_add_to_physmap
interface was proving to be a bit tricky so we have decided to go with
a new interface upstream (the XENMAPSPACE_gmfn_foreign interface using
XENMEM_add_to_physmap was never committed anywhere). This interface
also allows for batching which was impossible to support at the same
time as foreign mfns in the old interface.

This reverts the relevant parts of "PVH: basic and header changes,
elfnote changes, ..." and followups and trivially converts
pvh_add_to_xen_p2m over.

Acked-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>