common: Drop linux/delay.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-imx/mx6/soc.c b/arch/arm/mach-imx/mx6/soc.c
index b8aaf3e..19ca382 100644
--- a/arch/arm/mach-imx/mx6/soc.c
+++ b/arch/arm/mach-imx/mx6/soc.c
@@ -8,6 +8,7 @@
 
 #include <common.h>
 #include <init.h>
+#include <linux/delay.h>
 #include <linux/errno.h>
 #include <asm/io.h>
 #include <asm/arch/imx-regs.h>