x86, numa, 32-bit: increase max_elements to 1024

so every element will represent 64M instead of 256M.

AMD opteron could have HW memory hole remapping, so could have
[0, 8g + 64M) on node0. Reduce element size to 64M to keep that on node 0

Later we need to use find_e820_area() to allocate memory_node_map like
on 64-bit. But need to move memory_present out of populate_mem_map...

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>