Squash to "selftests: mptcp: add mptcp_lib_get_counter"

Please add this line into the commit log:

'''
Use this helper in test_prio() in userspace_pm.sh too instead of
open-coding.
'''

Signed-off-by: Geliang Tang <geliang.tang@suse.com>

tools/testing/selftests/net/mptcp/userspace_pm.sh

@@ -874,19 +874,21 @@ test_prio()
 
 	# Check TX
 	print_test "MP_PRIO TX"
-	count=$(ip netns exec "$ns2" nstat -as | grep MPTcpExtMPPrioTx | awk '{print $2}')
-	[ -z "$count" ] && count=0
-	if [ $count != 1 ]; then
+	count=$(mptcp_lib_get_counter "$ns2" "MPTcpExtMPPrioTx")
+	if [ -z "$count" ]; then
+		test_skip
+	elif [ $count != 1 ]; then
 		test_fail "Count != 1: ${count}"
 	else
 		test_pass
 	fi
 
 	# Check RX
 	print_test "MP_PRIO RX"
-	count=$(ip netns exec "$ns1" nstat -as | grep MPTcpExtMPPrioRx | awk '{print $2}')
-	[ -z "$count" ] && count=0
-	if [ $count != 1 ]; then
+	count=$(mptcp_lib_get_counter "$ns1" "MPTcpExtMPPrioRx")
+	if [ -z "$count" ]; then
+		test_skip
+	elif [ $count != 1 ]; then
 		test_fail "Count != 1: ${count}"
 	else
 		test_pass