Now we set up cpu_possible_map early we can dynamically allocate the
emergency stacks.  Previously we would allocate NR_CPUS * PAGE_SIZE,
potentially wasting quite a lot of memory.

Clean a comment up in irqstack_early_init and use unsigned int for cpu ids
while in the area.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>