vmlinux.lds.h update

Updated after review by Tim Abbott.
- Use HEAD_TEXT_SECTION
- Drop use of section-names.h and delete file
- Introduce EXIT_CALL

Deleting section-names.h required a few simple
updates of init.h

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Tim Abbott <tabbott@ksplice.com>

include/linux/init.h

@@ -2,8 +2,6 @@
 #define _LINUX_INIT_H
 
 #include <linux/compiler.h>
-#include <linux/section-names.h>
-#include <linux/stringify.h>
 
 /* These macros are used to mark some functions or 
  * initialized data (doesn't apply to uninitialized data)
@@ -101,7 +99,7 @@
 #define __memexitconst   __section(.memexit.rodata)
 
 /* For assembly routines */
-#define __HEAD		.section	__stringify(HEAD_TEXT_SECTION),"ax"
+#define __HEAD		.section	".head.text","ax"
 #define __INIT		.section	".init.text","ax"
 #define __FINIT		.previous