Update to v4.20.1 kernel headers.

This includes one manual change:

In the file bionic/libc/kernel/uapi/linux/in.h, the macro IN_BADCLASS
was not definied correctly. Change the macro from:

  #define IN_BADCLASS(a) ((((long int) (a)) == 0xffffffff)

to:

  #define IN_BADCLASS(a) (((long int) (a)) == (long int)0xffffffff)

This change is being pushed to the upstream kernels.

Test: Builds and boots.
Change-Id: Ia304773a9dc6789b34d9769d73742384d6afb571
Merged-In: Ia304773a9dc6789b34d9769d73742384d6afb571
(cherry picked from commit 967fb01cce73591281e7804e2c0fa9f83b618f5b)
diff --git a/libc/kernel/uapi/linux/netlink.h b/libc/kernel/uapi/linux/netlink.h
index 4f35c02..4c0fd1f 100644
--- a/libc/kernel/uapi/linux/netlink.h
+++ b/libc/kernel/uapi/linux/netlink.h
@@ -112,6 +112,7 @@
 #define NETLINK_LIST_MEMBERSHIPS 9
 #define NETLINK_CAP_ACK 10
 #define NETLINK_EXT_ACK 11
+#define NETLINK_GET_STRICT_CHK 12
 struct nl_pktinfo {
   __u32 group;
 };