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/sandbox/cpu/cpu.c b/arch/sandbox/cpu/cpu.c
index 0d93007..fb857e5 100644
--- a/arch/sandbox/cpu/cpu.c
+++ b/arch/sandbox/cpu/cpu.c
@@ -9,6 +9,7 @@
 #include <dm.h>
 #include <errno.h>
 #include <log.h>
+#include <linux/delay.h>
 #include <linux/libfdt.h>
 #include <os.h>
 #include <asm/io.h>