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/magic.h b/libc/kernel/uapi/linux/magic.h
index 68b4c65..bf57a58 100644
--- a/libc/kernel/uapi/linux/magic.h
+++ b/libc/kernel/uapi/linux/magic.h
@@ -45,6 +45,7 @@
 #define HPFS_SUPER_MAGIC 0xf995e849
 #define ISOFS_SUPER_MAGIC 0x9660
 #define JFFS2_SUPER_MAGIC 0x72b6
+#define XFS_SUPER_MAGIC 0x58465342
 #define PSTOREFS_MAGIC 0x6165676C
 #define EFIVARFS_MAGIC 0xde5e81e4
 #define HOSTFS_SUPER_MAGIC 0x00c0ffee