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/P1023RDB.h b/include/configs/P1023RDB.h
index 2f3831e..6bf3cd5 100644
--- a/include/configs/P1023RDB.h
+++ b/include/configs/P1023RDB.h
@@ -9,6 +9,8 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
+#include <linux/stringify.h>
+
 #ifndef CONFIG_SYS_MONITOR_BASE
 #define CONFIG_SYS_MONITOR_BASE	CONFIG_SYS_TEXT_BASE	/* start of monitor */
 #endif