Pull misc build failure fixes from Mike Rapoport:
"Fix min_low_pfn/max_low_pfn build errors on ia64 and microblaze.
Some configurations of ia64 and microblaze use min_low_pfn and
max_low_pfn in pfn_valid(). This causes build failures for modules
that use pfn_valid().
The fix is to add EXPORT_SYMBOL() for these variables on ia64 and
microblaze"
* tag 'fixes-2020-09-03' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
ia64: fix min_low_pfn/max_low_pfn build errors
microblaze: fix min_low_pfn/max_low_pfn build errors