common: Drop linux/stringify.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/cyrus.h b/include/configs/cyrus.h
index 9ab92e6..052e601 100644
--- a/include/configs/cyrus.h
+++ b/include/configs/cyrus.h
@@ -6,6 +6,8 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
+#include <linux/stringify.h>
+
 #if !defined(CONFIG_ARCH_P5020) && !defined(CONFIG_ARCH_P5040)
 #error Must call Cyrus CONFIG with a specific CPU enabled.
 #endif