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/MPC8555CDS.h b/include/configs/MPC8555CDS.h
index f0fe469..ea460e6 100644
--- a/include/configs/MPC8555CDS.h
+++ b/include/configs/MPC8555CDS.h
@@ -448,7 +448,7 @@
 
 #define CONFIG_HOSTNAME  unknown
 #define CONFIG_ROOTPATH  "/nfsroot"
-#define CONFIG_BOOTFILE  your.uImage
+#define CONFIG_BOOTFILE  "your.uImage"
 
 #define CONFIG_SERVERIP  192.168.1.1
 #define CONFIG_GATEWAYIP 192.168.1.1