x86: Only call dma32_reserve_bootmem 64bit !CONFIG_NUMA

64bit NUMA already make enough space under 4G with new early_node_mem.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-16-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>