COMMON: Use __stringify() instead of rest of implementations

Fix up the rest of implementations of __stringify().

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
diff --git a/board/logicpd/zoom2/zoom2_serial.h b/board/logicpd/zoom2/zoom2_serial.h
index 4e30587..ad63a07 100644
--- a/board/logicpd/zoom2/zoom2_serial.h
+++ b/board/logicpd/zoom2/zoom2_serial.h
@@ -22,6 +22,8 @@
 #ifndef ZOOM2_SERIAL_H
 #define ZOOM2_SERIAL_H
 
+#include <linux/stringify.h>
+
 extern int zoom2_debug_board_connected (void);
 
 #define SERIAL_TL16CP754C_BASE	0x10000000	/* Zoom2 Serial chip address */
@@ -31,9 +33,6 @@
 #define QUAD_BASE_2	(SERIAL_TL16CP754C_BASE + 0x200)
 #define QUAD_BASE_3	(SERIAL_TL16CP754C_BASE + 0x300)
 
-#define S(a) #a
-#define N(a) S(quad##a)
-
 #define QUAD_INIT(n)				\
 int quad_init_##n(void)				\
 {						\
@@ -61,7 +60,7 @@
 }						\
 struct serial_device zoom2_serial_device##n =	\
 {						\
-	N(n),					\
+	__stringify(n),				\
 	quad_init_##n,				\
 	NULL,					\
 	quad_setbrg_##n,			\