drm/i915: delete gpu reloc code

It's already removed, this just garbage collects it all.

v2: Rebase over s/GEN/GRAPHICS_VER/

v3: Also ditch eb.reloc_pool and eb.reloc_context (Maarten)
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20210803124833.3817354-2-daniel.vetter@ffwll.ch

drivers/gpu/drm/i915/selftests/i915_live_selftests.h

@@ -38,7 +38,6 @@ selftest(gem, i915_gem_live_selftests)
 selftest(evict, i915_gem_evict_live_selftests)
 selftest(hugepages, i915_gem_huge_page_live_selftests)
 selftest(gem_contexts, i915_gem_context_live_selftests)
-selftest(gem_execbuf, i915_gem_execbuffer_live_selftests)
 selftest(client, i915_gem_client_blt_live_selftests)
 selftest(gem_migrate, i915_gem_migrate_live_selftests)
 selftest(reset, intel_reset_live_selftests)