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/drivers/ram/rockchip/sdram_rk322x.c b/drivers/ram/rockchip/sdram_rk322x.c
index 0b11b48..094693c 100644
--- a/drivers/ram/rockchip/sdram_rk322x.c
+++ b/drivers/ram/rockchip/sdram_rk322x.c
@@ -20,6 +20,7 @@
 #include <asm/arch-rockchip/uart.h>
 #include <asm/arch-rockchip/sdram.h>
 #include <asm/types.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 
 DECLARE_GLOBAL_DATA_PTR;