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/gen_stats.h b/libc/kernel/uapi/linux/gen_stats.h
index 127ae88..0b6c228 100644
--- a/libc/kernel/uapi/linux/gen_stats.h
+++ b/libc/kernel/uapi/linux/gen_stats.h
@@ -27,6 +27,7 @@
   TCA_STATS_APP,
   TCA_STATS_RATE_EST64,
   TCA_STATS_PAD,
+  TCA_STATS_BASIC_HW,
   __TCA_STATS_MAX,
 };
 #define TCA_STATS_MAX (__TCA_STATS_MAX - 1)