common: cosmetic: CONFIG_BOOTFILE checkpatch compliance

Remove MK_STR from places that consume CONFIG_BOOTFILE to force all definitions to be string literals.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Joe Hershberger <joe.hershberger@gmail.com>
Cc: Wolfgang Denk <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/include/configs/MPC8572DS.h b/include/configs/MPC8572DS.h
index 547f752..ffee8fc 100644
--- a/include/configs/MPC8572DS.h
+++ b/include/configs/MPC8572DS.h
@@ -723,7 +723,7 @@
 
 #define CONFIG_HOSTNAME		unknown
 #define CONFIG_ROOTPATH		"/opt/nfsroot"
-#define CONFIG_BOOTFILE		uImage
+#define CONFIG_BOOTFILE		"uImage"
 #define CONFIG_UBOOTPATH	u-boot.bin	/* U-Boot image on TFTP server */
 
 #define CONFIG_SERVERIP		192.168.1.1