PCI/AER: Unify error bit printing for native and CPER reporting

AER errors can be reported natively (Linux AER driver fields interrupts and
reads error state directly from hardware) or via the ACPI/APEI/GHES/CPER
path (platform firmware reads error state from hardware and sends it to
Linux via ACPI interfaces).

Previously the same error would produce different output depending on
whether it was reported natively or via ACPI.  The CPER path resulted in
hard-to-understand messages, without a prefix. Instead use
__aer_print_error() for both native AER and CPER to provide a more
consistent log format.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>