Update to v6.1 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-6.1

Test: Bionic unit tests pass.
Change-Id: I9414fb5e698a9806b85eb09e37d763849f08a468
diff --git a/libc/kernel/uapi/linux/pkt_cls.h b/libc/kernel/uapi/linux/pkt_cls.h
index 580e83e..876cb73 100644
--- a/libc/kernel/uapi/linux/pkt_cls.h
+++ b/libc/kernel/uapi/linux/pkt_cls.h
@@ -462,6 +462,7 @@
   TCA_FLOWER_KEY_NUM_OF_VLANS,
   TCA_FLOWER_KEY_PPPOE_SID,
   TCA_FLOWER_KEY_PPP_PROTO,
+  TCA_FLOWER_KEY_L2TPV3_SID,
   __TCA_FLOWER_MAX,
 };
 #define TCA_FLOWER_MAX (__TCA_FLOWER_MAX - 1)