x86/xen: do not use _PAGE_IOMAP PTE flag for I/O mappings
x86/xen: do not use _PAGE_IOMAP PTE flag for I/O mappings

Since mfn_to_pfn() returns the correct PFN for identity mappings (as
used for MMIO regions), the use of _PAGE_IOMAP is not required in
pte_mfn_to_pfn().

Do not set the _PAGE_IOMAP flag in pte_pfn_to_mfn() and do not use it
in pte_mfn_to_pfn().

This will allow _PAGE_IOMAP to be removed, making it available for
future use.

Signed-off-by: David Vrabel <b9d45bd1f671e508cd8daa63dfc3cabb597562df@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <da3a51b335cef0eb0e2c329c5ef6bcd6acef687a@oracle.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs