powerpc/powernv/eeh/npu: Fix uninitialized variables in opal_pci_eeh_freeze_status

[ Upstream commit c20577014f85f36d4e137d3d52a1f61225b4a3d2 ]

The current implementation of the OPAL_PCI_EEH_FREEZE_STATUS call in
skiboot's NPU driver does not touch the pci_error_type parameter so
it might have garbage but the powernv code analyzes it nevertheless.

This initializes pcierr and fstate to zero in all call sites.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>