vfio-pci: Use io_remap_pfn_range() for PCI IO memory

commit f8f6ae5d07 ("mm: always have io_remap_pfn_range() set
pgprot_decrypted()") allows drivers using mmap to put PCI memory mapped
BAR space into userspace to work correctly on AMD SME systems that default
to all memory encrypted.

Since vfio_pci_mmap_fault() is working with PCI memory mapped BAR space it
should be calling io_remap_pfn_range() otherwise it will not work on SME
systems.

Fixes: 11c4cd07ba ("vfio-pci: Fault mmaps to enable vma tracking")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Peter Xu <peterx@redhat.com>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/pci/vfio_pci.c

@@ -1633,8 +1633,8 @@ static vm_fault_t vfio_pci_mmap_fault(struct vm_fault *vmf)
 
 	mutex_unlock(&vdev->vma_lock);
 
-	if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
-			    vma->vm_end - vma->vm_start, vma->vm_page_prot))
+	if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
+			       vma->vm_end - vma->vm_start, vma->vm_page_prot))
 		ret = VM_FAULT_SIGBUS;
 
 up_out: