memblock test: Update TODO list

Remove the completed items from TODO list.

Signed-off-by: Shaoqin Huang <shaoqin.huang@intel.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20221011062128.49359-4-shaoqin.huang@intel.com