If Local memory is supported by hardware, we want framebuffer backing
gem objects from local memory.

if the backing obj is not from LMEM, pin_to_display is failed.

v2:
  memory regions are correctly assigned to obj->memory_regions [tvrtko]
  migration failure is reported as debug log [Tvrtko]
v3:
  Migration is dropped. only error is reported [Daniel]
  mem region check is move to pin_to_display [Chris]
v4:
  s/dev_priv/i915 [chris]
v5:
  i915_gem_object_is_lmem is used for detecting the obj mem type. [Matt]

cc: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191105144414.30470-1-ramalingam.c@intel.com