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/mips/mach-ath79/reset.c b/arch/mips/mach-ath79/reset.c
index 0ab3ab6..62330a6 100644
--- a/arch/mips/mach-ath79/reset.c
+++ b/arch/mips/mach-ath79/reset.c
@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <linux/delay.h>
 #include <linux/errno.h>
 #include <asm/io.h>
 #include <asm/addrspace.h>