drm/xe: Use DRM GPUVM helpers for external- and evicted objects

drm/xe: Use DRM GPUVM helpers for external- and evicted objects

Adapt to the DRM_GPUVM helpers moving removing a lot of complicated
driver-specific code.

For now this uses fine-grained locking for the evict list and external
object list, which may incur a slight performance penalty in some
situations.

v2:
- Don't lock all bos and validate on LR exec submissions (Matthew Brost)
- Add some kerneldoc

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231212100144.6833-2-thomas.hellstrom@linux.intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>