DscpPolicy Move to kernel 5.15

Require at least kernel 5.15. Feature is not required on older
kernels and may impact boot time unnecessarily.

Bug: 235559605
BUg: 241077401
Fixes: 241077401
Test: run cts -m CtsNetTestCases -t android.net.cts.DscpPolicyTest
Change-Id: I2e4b509de1d8940fc63ae057a8326f13c0fd1420
Merged-In: I2e4b509de1d8940fc63ae057a8326f13c0fd1420

tests/cts/net/src/android/net/cts/DscpPolicyTest.kt

@@ -136,8 +136,8 @@ class DscpPolicyTest {
 
     @Before
     fun setUp() {
-        // For BPF support kernel needs to be at least 5.4.
-        assumeTrue(kernelIsAtLeast(5, 4))
+        // For BPF support kernel needs to be at least 5.15.
+        assumeTrue(kernelIsAtLeast(5, 15))
 
         runAsShell(MANAGE_TEST_NETWORKS) {
             val tnm = realContext.getSystemService(TestNetworkManager::class.java)
@@ -158,7 +158,7 @@ class DscpPolicyTest {
 
     @After
     fun tearDown() {
-        if (!kernelIsAtLeast(5, 4)) {
+        if (!kernelIsAtLeast(5, 15)) {
             return;
         }
         agentsToCleanUp.forEach { it.unregister() }