maple_tree: fix node allocation testing on 32 bit

Internal node counting was altered and the 64 bit test was updated,
however the 32bit test was missed.

Restore the 32bit test to a functional state.

Link: https://lore.kernel.org/linux-mm/CAMuHMdV4T53fOw7VPoBgPR7fP6RYqf=CBhD_y_vOg53zZX_DnA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20230712173916.168805-2-Liam.Howlett@oracle.com


Fixes: 541e06b7 ("maple_tree: remove GFP_ZERO from kmem_cache_alloc() and kmem_cache_alloc_bulk()")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>