kbuild: whitelist section mismatch in init/main.c

In init/main.c we have a reference from rest_init() to .init.text
which is intentional.
Rename the function 'init' to 'kernel_init' to make it a
kernel wide unique symbol and whitelist the reference.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/init/main.c b/init/main.c
index a92989e..7a92b4c 100644
--- a/init/main.c
+++ b/init/main.c
@@ -82,7 +82,7 @@
 #warning gcc-4.1.0 is known to miscompile the kernel.  A different compiler version is recommended.
 #endif
 
-static int init(void *);
+static int kernel_init(void *);
 
 extern void init_IRQ(void);
 extern void fork_init(unsigned long);
@@ -435,7 +435,7 @@
 static void noinline rest_init(void)
 	__releases(kernel_lock)
 {
-	kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
+	kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 	numa_default_policy();
 	unlock_kernel();
 
@@ -772,7 +772,7 @@
 	panic("No init found.  Try passing init= option to kernel.");
 }
 
-static int __init init(void * unused)
+static int __init kernel_init(void * unused)
 {
 	lock_kernel();
 	/*