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/time.h b/libc/kernel/uapi/linux/time.h
index eed430b..df52295 100644
--- a/libc/kernel/uapi/linux/time.h
+++ b/libc/kernel/uapi/linux/time.h
@@ -31,13 +31,6 @@
   __kernel_old_time_t tv_sec;
   __kernel_suseconds_t tv_usec;
 };
-struct timezone {
-  int tz_minuteswest;
-  int tz_dsttime;
-};
-#define ITIMER_REAL 0
-#define ITIMER_VIRTUAL 1
-#define ITIMER_PROF 2
 struct itimerspec {
   struct timespec it_interval;
   struct timespec it_value;
@@ -46,6 +39,13 @@
   struct timeval it_interval;
   struct timeval it_value;
 };
+struct timezone {
+  int tz_minuteswest;
+  int tz_dsttime;
+};
+#define ITIMER_REAL 0
+#define ITIMER_VIRTUAL 1
+#define ITIMER_PROF 2
 #define CLOCK_REALTIME 0
 #define CLOCK_MONOTONIC 1
 #define CLOCK_PROCESS_CPUTIME_ID 2