linux-next build failure on arm64 with CMA but !NUMA

[Guido Günther <agx@xxxxxxxxxxx>]

Hi Roman,
882d60d2ce725381236a158204d7ec13ff19ab25 in linux-next broke compilation
on arm64 CMA && !NUMA like

  CC      kernel/irq/irqdesc.o
mm/hugetlb.c: In function ‘hugetlb_cma_reserve’:
mm/hugetlb.c:5449:3: error: implicit declaration of function ‘for_each_mem_pfn_range’; did you mean ‘for_each_mem_range’? [-Werror=implicit-function-declaration]
   for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
   ^~~~~~~~~~~~~~~~~~~~~~ 
   for_each_mem_range
mm/hugetlb.c:5449:61: error: expected ‘;’ before ‘{’ token
   for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
                                                             ^~
Reverting that fixes the build for the moment. Would making all of this
dependent on CMA && NUMA be the right fix?
Cheers,
 -- Guido