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-sunxi/dram_sun6i.c b/arch/arm/mach-sunxi/dram_sun6i.c
index 8e78126..0590110 100644
--- a/arch/arm/mach-sunxi/dram_sun6i.c
+++ b/arch/arm/mach-sunxi/dram_sun6i.c
@@ -16,6 +16,7 @@
 #include <asm/arch/clock.h>
 #include <asm/arch/dram.h>
 #include <asm/arch/prcm.h>
+#include <linux/delay.h>
 
 #define DRAM_CLK (CONFIG_DRAM_CLK * 1000000)