Update to v6.0 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-6.0

Test: Boots on coral.
Test: Bionic unit tests pass.
Change-Id: I282de83f23b432bef58214108a93700bdadddf0f
diff --git a/libc/kernel/uapi/linux/virtio_9p.h b/libc/kernel/uapi/linux/virtio_9p.h
index 1d9dfb1..2e05786 100644
--- a/libc/kernel/uapi/linux/virtio_9p.h
+++ b/libc/kernel/uapi/linux/virtio_9p.h
@@ -24,6 +24,6 @@
 #define VIRTIO_9P_MOUNT_TAG 0
 struct virtio_9p_config {
   __virtio16 tag_len;
-  __u8 tag[0];
+  __u8 tag[];
 } __attribute__((packed));
 #endif