Use the crash handler hooks to run the SPU stop code, just like we do for
ehea and cell RAS code.

While I'm here I noticed "CPUSs reliabally"

so fix the spelling MISTAKESs reliabally.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>