xen/mmu/enlighten: Fix memblock_x86_reserve_range downport.

xen/mmu/enlighten: Fix memblock_x86_reserve_range downport.

This is not for upstream as it memblock_x86_reserve_range is not
used upstream anymore.

When I back-ported the patches:
xen/x86: Use memblock_reserve for sensitive areas.
xen/mmu: Recycle the Xen provided L4, L3, and L2 pages

I simply used sed s/memblock_reserve/memblock_x86_reserve_range/.
That was incorrect as the parameters are different - memblock_reserve
as second expects the size, while memblock_x86_reserve_range expects
the physical address. This patch fixes those bugs.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>