vmlinux.lds.h: remove unused CPU_KEEP and CPU_DISCARD macros

Remove the left-over of commit e24f6628 ("modpost: remove all
traces of cpuinit/cpuexit sections").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Paul Gortmaker <paul.gortmaker@windriver.com>

include/asm-generic/vmlinux.lds.h

@@ -138,13 +138,6 @@
  * are handled as text/data or they can be discarded (which
  * often happens at runtime)
  */
-#ifdef CONFIG_HOTPLUG_CPU
-#define CPU_KEEP(sec)    *(.cpu##sec)
-#define CPU_DISCARD(sec)
-#else
-#define CPU_KEEP(sec)
-#define CPU_DISCARD(sec) *(.cpu##sec)
-#endif
 
 #if defined(CONFIG_MEMORY_HOTPLUG)
 #define MEM_KEEP(sec)    *(.mem##sec)