powerpc/eeh: Make EEH handler PE sensitive

Once eeh error is found, eeh event will be created and put it into
the global linked list. At the mean while, kernel thread will be
started to process it. The handler for the kernel thread originally
was eeh device sensitive.

The patch reworks the handler of the kernel thread so that it's PE
sensitive.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>