init/main.c: make "initcall_level_names[]" const char *

Initcall names should not be changed.

Link: http://lkml.kernel.org/r/20181124091829.GD10969@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

init/main.c

diff --git a/init/main.c b/init/main.c
index 86d8948..6a74ba0 100644
--- a/init/main.c
+++ b/init/main.c
@@ -930,7 +930,7 @@ static initcall_entry_t *initcall_levels[] __initdata = {
 };
 
 /* Keep these in sync with initcalls in include/linux/init.h */
-static char *initcall_level_names[] __initdata = {
+static const char *initcall_level_names[] __initdata = {
 	"pure",
 	"core",
 	"postcore",