Currently the snsc driver uses force_sig to send init a SIGPWR when the
system overheats.  This patch switches it to kill_proc instead which has
the following advantages:

 (1) gets rid of one of the last remaining tasklist_lock users
     in modular code
 (2) simplifies the snsc code significantly

The downside is that an init implementation could in theory block SIGPWR
and it would not get delivered.  The sysvinit code used by all major
distributions doesn't do this and blocking this signal in init would be a
rather stupid thing to do.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>