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/ddr/fsl/fsl_mmdc.c b/drivers/ddr/fsl/fsl_mmdc.c
index 0828512..cbd625b 100644
--- a/drivers/ddr/fsl/fsl_mmdc.c
+++ b/drivers/ddr/fsl/fsl_mmdc.c
@@ -10,6 +10,7 @@
 #include <common.h>
 #include <fsl_mmdc.h>
 #include <asm/io.h>
+#include <linux/delay.h>
 
 static void set_wait_for_bits_clear(void *ptr, u32 value, u32 bits)
 {