[PATCH] powerpc: Add support for the MPC83xx watchdog

Add support for the PowerPC MPC83xx watchdog.  The MPC83xx has a simple
watchdog that once enabled it can not be stopped, has some simple timeout
range selection, and the ability to either reset the processor or take a
machine check.

Signed-off-by: Dave Updegraff <dave@cray.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>