drm/i915/gvt: remove the map_gfn_to_mfn and set_trap_area ops

The map_gfn_to_mfn and set_trap_area ops are never defined, so remove
them and clean up code that depends on them in the callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220411141403.86980-9-hch@lst.de


Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>