The copy_to_user() function returns the number of bytes that were not
copied but we want to return -EFAULT on error here.
Fixes: 188ad9d6cbbc ('vfio/pci: Include sparse mmap capability for MSI-X table regions')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>