gvt_pin_guest_page extracted some of the gvt_dma_map_page functionality:
commit 
79e542f5af79 ("drm/i915/kvmgt: Support setting dma map for huge pages")
And yet, part of it was reintroduced in:
commit 
39b4cbadb9a9 ("drm/i915/kvmgt: Check the pfn got from vfio_pin_pages")
Causing kvmgt part to no longer build. Let's remove it.
Reported-by: Tomasz Lis <tomasz.lis@intel.com>
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Acked-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712155330.32055-1-michal.winiarski@intel.com
 
        if (ret)
                return ret;
 
-       if (!pfn_valid(pfn)) {
-               gvt_vgpu_err("pfn 0x%lx is not mem backed\n", pfn);
-               vfio_unpin_pages(mdev_dev(vgpu->vdev.mdev), &gfn, 1);
-               return -EINVAL;
-       }
-
        /* Setup DMA mapping. */
        *dma_addr = dma_map_page(dev, page, 0, size, PCI_DMA_BIDIRECTIONAL);
        ret = dma_mapping_error(dev, *dma_addr);