COMMON: Use __stringify() instead of MK_STR()

Kill multiple occurances and redeclaration of MK_STR
in favor of __stringify().

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/include/configs/bf537-srv1.h b/include/configs/bf537-srv1.h
index 52d5d97..1de8ffe 100644
--- a/include/configs/bf537-srv1.h
+++ b/include/configs/bf537-srv1.h
@@ -173,7 +173,7 @@
 
 #define BOOT_ENV_SETTINGS \
 	"update=tftpboot $(loadaddr) u-boot.ldr;" \
-		"sf probe " MK_STR(BFIN_BOOT_SPI_SSEL) ";" \
+		"sf probe " __stringify(BFIN_BOOT_SPI_SSEL) ";" \
 		"sf erase 0 0x30000;" \
 		"sf write $(loadaddr) 0 $(filesize)" \
 	"flashboot=sf read 0x1000000 0x30000 0x320000;" \