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/xpedite517x.h b/include/configs/xpedite517x.h
index 6c9991f..d3bb929 100644
--- a/include/configs/xpedite517x.h
+++ b/include/configs/xpedite517x.h
@@ -51,6 +51,7 @@
 #define CONFIG_SYS_SCRATCH_VA	0xe0000000
 
 #ifndef __ASSEMBLY__
+#include <linux/stringify.h>
 extern unsigned long get_board_sys_clk(unsigned long dummy);
 #endif