QM: Add support for handling DSCP request

Add support to parse DSCP policy control interface events received from
wpa_supplicant and maintain DSCP policy table entries accordingly.

Send solicited DSCP response corresponding to received DSCP request.

Add nft rules for policies without domain name attribute.

Set iperf traffic's DSCP value from policy table if a matching domain
name policy is found.

Signed-off-by: Veerendranath Jakkam <vjakkam@codeaurora.org>
diff --git a/utils.c b/utils.c
index eca6e2d..029b989 100644
--- a/utils.c
+++ b/utils.c
@@ -1033,3 +1033,9 @@
 
 	return 0;
 }
+
+
+int snprintf_error(size_t size, int res)
+{
+	return res < 0 || (unsigned int) res >= size;
+}