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/drm/nouveau_drm.h b/libc/kernel/uapi/drm/nouveau_drm.h
index 186ffcc..150f729 100644
--- a/libc/kernel/uapi/drm/nouveau_drm.h
+++ b/libc/kernel/uapi/drm/nouveau_drm.h
@@ -92,6 +92,7 @@
   __u64 push;
   __u32 suffix0;
   __u32 suffix1;
+#define NOUVEAU_GEM_PUSHBUF_SYNC (1ULL << 0)
   __u64 vram_available;
   __u64 gart_available;
 };