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/arm/mach-stm32/soc.c b/arch/arm/mach-stm32/soc.c
index 41338a1..1f12da4 100644
--- a/arch/arm/mach-stm32/soc.c
+++ b/arch/arm/mach-stm32/soc.c
@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <init.h>
 #include <asm/io.h>
 #include <asm/armv7_mpu.h>