drm/vmwgfx: Free hash table allocated by cmdbuf managed res mgr

BugLink: http://bugs.launchpad.net/bugs/1702863

commit 82fcee52 upstream.

The hash table created during vmw_cmdbuf_res_man_create was
never freed. This causes memory leak in context creation.
Added the corresponding drm_ht_remove in vmw_cmdbuf_res_man_destroy.

Tested for memory leak by running piglit overnight and kernel
memory is not inflated which earlier was.
Signed-off-by: Deepak Rawat <drawat@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf_res.c

@@ -321,6 +321,7 @@ void vmw_cmdbuf_res_man_destroy(struct vmw_cmdbuf_res_manager *man)
 	list_for_each_entry_safe(entry, next, &man->list, head)
 		vmw_cmdbuf_res_free(man, entry);
 
+	drm_ht_remove(&man->resources);
 	kfree(man);
 }