common: cosmetic: CONFIG_ROOTPATH checkpatch compliance

Remove MK_STR from places that consume CONFIG_ROOTPATH 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/P1_P2_RDB.h b/include/configs/P1_P2_RDB.h
index ba74a15..765477a 100644
--- a/include/configs/P1_P2_RDB.h
+++ b/include/configs/P1_P2_RDB.h
@@ -642,7 +642,7 @@
 #endif
 
 #define CONFIG_HOSTNAME		P2020RDB
-#define CONFIG_ROOTPATH		/opt/nfsroot
+#define CONFIG_ROOTPATH		"/opt/nfsroot"
 #define CONFIG_BOOTFILE		uImage
 #define CONFIG_UBOOTPATH	u-boot.bin/* U-Boot image on TFTP server */