x86: fix setup of PVH Dom0 memory map

x86: fix setup of PVH Dom0 memory map

This patch adds the holes removed by MMIO regions to the end of the
memory map for PVH Dom0, so the guest OS doesn't have to manually
populate this memory.

Also, provide a suitable e820 memory map for PVH Dom0, that matches
the underlying p2m map. This means that PVH guests should always use
XENMEM_memory_map in order to obtain the e820, even when running as
Dom0.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>