PCI: Add PCI_STD_NUM_BARS for the number of standard BARs

Code that iterates over all standard PCI BARs typically uses
PCI_STD_RESOURCE_END.  However, that requires the unusual test
"i <= PCI_STD_RESOURCE_END" rather than something the typical
"i < PCI_STD_NUM_BARS".

Add a definition for PCI_STD_NUM_BARS and change loops to use the more
idiomatic C style to help avoid fencepost errors.

Link: https://lore.kernel.org/r/20190927234026.23342-1-efremov@linux.com
Link: https://lore.kernel.org/r/20190927234308.23935-1-efremov@linux.com
Link: https://lore.kernel.org/r/20190916204158.6889-3-efremov@linux.com
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Sebastian Ott <sebott@linux.ibm.com>			# arch/s390/
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>	# video/fbdev/
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>	# pci/controller/dwc/
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>		# scsi/pm8001/
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>	# scsi/pm8001/
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>			# memstick/

drivers/scsi/pm8001/pm8001_hwi.c

@@ -1186,7 +1186,7 @@ static void pm8001_hw_chip_rst(struct pm8001_hba_info *pm8001_ha)
 void pm8001_chip_iounmap(struct pm8001_hba_info *pm8001_ha)
 {
 	s8 bar, logical = 0;
-	for (bar = 0; bar < 6; bar++) {
+	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
 		/*
 		** logical BARs for SPC:
 		** bar 0 and 1 - logical BAR0