PCI/DPC: Make RP PIO log size check more generic

In dpc_probe(), we set dpc->rp_log_size to zero if we think the hardware
reports an invalid size.  In this case, we could have dpc->rp_extensions
set but dpc->rp_log_size == 0, and we should print the basic RP PIO
registers but not the variable-size portion.  We already checked for
dpc->rp_log_size < 4 above, so this patch is just for consistency of style.
No functional change intended.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sinan Kaya <okaya@codeaurora.org>

drivers/pci/pcie/pcie-dpc.c

@@ -212,11 +212,12 @@ static void dpc_rp_pio_get_info(struct dpc_dev *dpc,
 			      &rp_pio->header_log.dw2);
 	pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_HEADER_LOG + 12,
 			      &rp_pio->header_log.dw3);
-	if (dpc->rp_log_size == 4)
-		return;
 
+	if (dpc->rp_log_size < 5)
+		return;
 	pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_IMPSPEC_LOG,
 			      &rp_pio->impspec_log);
+
 	for (i = 0; i < dpc->rp_log_size - 5; i++)
 		pci_read_config_dword(pdev,
 			cap + PCI_EXP_DPC_RP_PIO_TLPPREFIX_LOG,