x86: Make 32bit support NO_BOOTMEM

Let's make 32bit consistent with 64bit.

-v2: Andrew pointed out for 32bit that we should use -1ULL

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-25-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>