common: Drop init.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/slimbootloader/slimbootloader.c b/arch/x86/cpu/slimbootloader/slimbootloader.c
index 21dcfb2..889fba5 100644
--- a/arch/x86/cpu/slimbootloader/slimbootloader.c
+++ b/arch/x86/cpu/slimbootloader/slimbootloader.c
@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <cpu_func.h>
+#include <init.h>
 #include <asm/arch/slimbootloader.h>
 
 DECLARE_GLOBAL_DATA_PTR;