Instead of both driver and TTM allocating memory finalize embedding the
ttm_resource object as base into the driver backends.

v2: fix typo in vmwgfx grid mgr and double init in amdgpu_vram_mgr.c
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210602100914.46246-10-christian.koenig@amd.com