mm: move array mem_section init code out of memory_present()

mm: move array mem_section init code out of memory_present()

Patch series "mm/init: minor clean up and improvement".

These are all observed when going through code flow during mm init.

This patch (of 7):

When CONFIG_SPARSEMEM_EXTREME is enabled, mem_section need be initialized
to point at a two-dimensional array, and its 1st dimension of length
NR_SECTION_ROOTS will be dynamically allocated.  Once the allocation is
done, it's available for all nodes.

So take the 1st dimension of mem_section initialization out of
memory_present()(), and put it into memblocks_present() which is a more
appripriate place.

Link: https://lkml.kernel.org/r/20240326061134.1055295-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20240326061134.1055295-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>