openvswitch: Use string_is_terminated() helper

Use string_is_terminated() helper instead of cpecific memchr() call.
This shows better the intention of the call.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20230208133153.22528-3-andriy.shevchenko@linux.intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/openvswitch/conntrack.c

@@ -9,6 +9,7 @@
 #include <linux/udp.h>
 #include <linux/sctp.h>
 #include <linux/static_key.h>
+#include <linux/string_helpers.h>
 #include <net/ip.h>
 #include <net/genetlink.h>
 #include <net/netfilter/nf_conntrack_core.h>
@@ -1383,7 +1384,7 @@ static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
 #endif
 		case OVS_CT_ATTR_HELPER:
 			*helper = nla_data(a);
-			if (!memchr(*helper, '\0', nla_len(a))) {
+			if (!string_is_terminated(*helper, nla_len(a))) {
 				OVS_NLERR(log, "Invalid conntrack helper");
 				return -EINVAL;
 			}
@@ -1404,7 +1405,7 @@ static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 		case OVS_CT_ATTR_TIMEOUT:
 			memcpy(info->timeout, nla_data(a), nla_len(a));
-			if (!memchr(info->timeout, '\0', nla_len(a))) {
+			if (!string_is_terminated(info->timeout, nla_len(a))) {
 				OVS_NLERR(log, "Invalid conntrack timeout");
 				return -EINVAL;
 			}