Update to v5.6 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-5.6

Add a new method for removing structures. This is to deal with the kernel
headers changing some definitions of timeval to __kernel_old_timeval
and itimerval to __kernel_old_itimerval. Remove the __kernel_old_XX
strutures and change the other structures to the previous definitions.

This only works so long as these structures stay the same, if they
diverge, then a different strategy will need to be implemented.

Test: Booted cuttlefish/walleye.
Test: Ran bionic-unit-tests on cuttlefish/walleye.
Change-Id: I0a61f4fa6e4155c602e0414d9b38c2e1637829af
diff --git a/libc/kernel/uapi/linux/tcp.h b/libc/kernel/uapi/linux/tcp.h
index 823583d..4dbb764 100644
--- a/libc/kernel/uapi/linux/tcp.h
+++ b/libc/kernel/uapi/linux/tcp.h
@@ -217,15 +217,17 @@
   TCP_NLA_DSACK_DUPS,
   TCP_NLA_REORD_SEEN,
   TCP_NLA_SRTT,
+  TCP_NLA_TIMEOUT_REHASH,
 };
 #define TCP_MD5SIG_MAXKEYLEN 80
-#define TCP_MD5SIG_FLAG_PREFIX 1
+#define TCP_MD5SIG_FLAG_PREFIX 0x1
+#define TCP_MD5SIG_FLAG_IFINDEX 0x2
 struct tcp_md5sig {
   struct sockaddr_storage tcpm_addr;
   __u8 tcpm_flags;
   __u8 tcpm_prefixlen;
   __u16 tcpm_keylen;
-  __u32 __tcpm_pad;
+  int tcpm_ifindex;
   __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];
 };
 struct tcp_diag_md5sig {