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/C29XPCIE.h b/include/configs/C29XPCIE.h
index 62ad50b..9a8cba6 100644
--- a/include/configs/C29XPCIE.h
+++ b/include/configs/C29XPCIE.h
@@ -10,6 +10,8 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
+#include <linux/stringify.h>
+
 #ifdef CONFIG_SPIFLASH
 #define CONFIG_RAMBOOT_SPIFLASH
 #define CONFIG_RESET_VECTOR_ADDRESS	0x110bfffc