sh: pci: Do PCI error check on own line

Instead of an "if" condition with a line split, use the usual error
handling pattern with a separate variable to improve readability.

No functional changes intended.

Link: https://lore.kernel.org/r/20230911125354.25501-3-ilpo.jarvinen@linux.intel.com


Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
[bhelgaas: u16 vid, PCI_POSSIBLE_ERROR()]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>