drm/ttm: Don't include drm_hashtab.h

Remove the include statement for drm_hashtab.h. It's not required
by TTM.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129094841.22499-2-tzimmermann@suse.de

include/drm/ttm/ttm_bo_api.h

@@ -32,7 +32,6 @@
 #define _TTM_BO_API_H_
 
 #include <drm/drm_gem.h>
-#include <drm/drm_hashtab.h>
 #include <drm/drm_vma_manager.h>
 #include <linux/kref.h>
 #include <linux/list.h>