Might be useful for SMP debugging.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

[Rewritten Kconfig bits to deal better fit in the usual pattern of doing
things - Ralf]
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>