mm: numa,memblock: include <asm/numa.h> for 'numa_nodes_parsed'

The 'numa_nodes_parsed' is defined in <asm/numa.h> but this file
is not included in mm/numa_memblks.c (build x86_64) so add this
to the incldues to fix the following sparse warning:

mm/numa_memblks.c:13:12: warning: symbol 'numa_nodes_parsed' was not declared. Should it be static?

Link: https://lkml.kernel.org/r/20260108101539.229192-1-ben.dooks@codethink.co.uk
Fixes: 87482708210f ("mm: introduce numa_memblks")
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>