PCI/AER: Use match_string() helper to simplify the code

task #29600094

commit 807ffb1e1eabbcdcd46494ee415317aa80ed415c upstream.
Backport summary: for 4.19 kernel ICX PCIe Gen4 support.

match_string() returns the array index of a matching string.  Use it
instead of the open-coded implementation.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
(cherry picked from commit 807ffb1e1eabbcdcd46494ee415317aa80ed415c)
Signed-off-by: NEthan Zhao <haifeng.zhao@intel.com>
Signed-off-by: NArtie Ding <artie.ding@linux.alibaba.com>
Acked-by: NCaspar Zhang <caspar@linux.alibaba.com>

drivers/pci/pcie/aer.c

@@ -117,7 +117,7 @@ bool pci_aer_available(void)
 
 static int ecrc_policy = ECRC_POLICY_DEFAULT;
 
-static const char *ecrc_policy_str[] = {
+static const char * const ecrc_policy_str[] = {
 	[ECRC_POLICY_DEFAULT] = "bios",
 	[ECRC_POLICY_OFF] = "off",
 	[ECRC_POLICY_ON] = "on"
@@ -203,11 +203,8 @@ void pcie_ecrc_get_policy(char *str)
 {
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(ecrc_policy_str); i++)
-		if (!strncmp(str, ecrc_policy_str[i],
-			     strlen(ecrc_policy_str[i])))
-			break;
-	if (i >= ARRAY_SIZE(ecrc_policy_str))
+	i = match_string(ecrc_policy_str, ARRAY_SIZE(ecrc_policy_str), str);
+	if (i < 0)
 		return;
 
 	ecrc_policy = i;