powerpc/eeh: More relaxed condition for enabled IO path

When one or both of the below two flags are marked in the PE state, the
PE's IO path is regarded as enabled: EEH_STATE_MMIO_ACTIVE or
EEH_STATE_MMIO_ENABLED.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>