ARM: 8394/1: update memblock limit after mapping lowmem

The memblock limit is currently used in find_limits
to find the bounds for ZONE_NORMAL. The memblock
limit may need to be rounded down a PMD size to ensure
allocations are fully mapped though. This has the side
effect of reducing the amount of memory in ZONE_NORMAL.
Once all lowmem is mapped, it's safe to change the memblock
limit back to include the unaligned section. Adjust the
memblock limit after lowmem mapping is complete.

Before:
 # cat /proc/zoneinfo | grep managed
        managed  62907
        managed  424

After:
 # cat /proc/zoneinfo | grep managed
        managed  63331
Signed-off-by: NLaura Abbott <labbott@fedoraproject.org>
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Tested-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/mmu.c

@@ -1519,6 +1519,7 @@ void __init paging_init(const struct machine_desc *mdesc)
 	build_mem_type_table();
 	prepare_page_table();
 	map_lowmem();
+	memblock_set_current_limit(arm_lowmem_limit);
 	dma_contiguous_remap();
 	devicemaps_init(mdesc);
 	kmap_init();