Revert "Update bionic kernel headers using update_all.py"

This reverts commit 94a85f663694e1869acb1c2e8a3c374a6fa3ab86

There is a smoke test failure for Prime but Crespo/Stingray are fine. Will revert the change for now until further investigation is made.
diff --git a/libc/kernel/arch-x86/asm/pgtable-2level-defs.h b/libc/kernel/arch-x86/asm/pgtable-2level-defs.h
index 9a60db5..9edc6c5 100644
--- a/libc/kernel/arch-x86/asm/pgtable-2level-defs.h
+++ b/libc/kernel/arch-x86/asm/pgtable-2level-defs.h
@@ -7,20 +7,16 @@
  ***   structures, and macros generated from the original header, and thus,
  ***   contains no copyrightable information.
  ***
- ***   To edit the content of this header, modify the corresponding
- ***   source file (e.g. under external/kernel-headers/original/) then
- ***   run bionic/libc/kernel/tools/update_all.py
- ***
- ***   Any manual change here will be lost the next time this script will
- ***   be run. You've been warned!
- ***
  ****************************************************************************
  ****************************************************************************/
 #ifndef _I386_PGTABLE_2LEVEL_DEFS_H
 #define _I386_PGTABLE_2LEVEL_DEFS_H
+
 #define SHARED_KERNEL_PMD 0
+
 #define PGDIR_SHIFT 22
-/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define PTRS_PER_PGD 1024
+
 #define PTRS_PER_PTE 1024
+
 #endif