powerpc/eeh: Don't check RTAS token to get PE addr

RTAS token "ibm,get-config-addr-info" or ibm,get-config-addr-info2"
are used to retrieve the PE address according to PCI address, which
made up of domain/bus/slot/function. If we don't have those 2 tokens,
the domain/bus/slot/function would be used as the address for EEH
RTAS operations. Some older f/w might not have those 2 tokens and
that blocks the EEH functionality to be initialized. It was introduced
by commit e2af155c ("powerpc/eeh: pseries platform EEH initialization").

The patch skips the check on those 2 tokens so we can bring up EEH
functionality successfully. And domain/bus/slot/function will be
used as address for EEH RTAS operations.

Cc: <stable@vger.kernel.org> # v3.4+
Reported-by: Robert Knight <knight@princeton.edu>
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Tested-by: Robert Knight <knight@princeton.edu>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>