KVM: ia64: Make pmt table be able to hold physical mmio entries.

Don't try to do put_page once the entries are mmio.
Set the tag to indicate the mmio space for vmm setting
TLB's memory attribute.

Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>