Update to v5.11 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-5.11

Test: Built cuttlefish and flame images. Ran bionic unit tests on both.
Change-Id: Ie60337aafad4bda55af99b6c8fe9f56bf2fa787f
diff --git a/libc/kernel/uapi/linux/ethtool.h b/libc/kernel/uapi/linux/ethtool.h
index 238c2d9..021a69b 100644
--- a/libc/kernel/uapi/linux/ethtool.h
+++ b/libc/kernel/uapi/linux/ethtool.h
@@ -18,7 +18,7 @@
  ****************************************************************************/
 #ifndef _UAPI_LINUX_ETHTOOL_H
 #define _UAPI_LINUX_ETHTOOL_H
-#include <linux/kernel.h>
+#include <linux/const.h>
 #include <linux/types.h>
 #include <linux/if_ether.h>
 #include <limits.h>