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/mips/mach-bmips/dram.c b/arch/mips/mach-bmips/dram.c
index 87ced7c..764ce89 100644
--- a/arch/mips/mach-bmips/dram.c
+++ b/arch/mips/mach-bmips/dram.c
@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <ram.h>
 #include <dm.h>