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/MPC837XERDB.h b/include/configs/MPC837XERDB.h
index 0163c6a..a26a5bb 100644
--- a/include/configs/MPC837XERDB.h
+++ b/include/configs/MPC837XERDB.h
@@ -644,7 +644,7 @@
 #define CONFIG_HOSTNAME		mpc837x_rdb
 #define CONFIG_ROOTPATH		"/nfsroot"
 #define CONFIG_RAMDISKFILE	rootfs.ext2.gz.uboot
-#define CONFIG_BOOTFILE		uImage
+#define CONFIG_BOOTFILE		"uImage"
 #define CONFIG_UBOOTPATH	u-boot.bin	/* U-Boot image on TFTP server */
 #define CONFIG_FDTFILE		mpc8379_rdb.dtb