efi_loader: size of media device path node represenation

In the format specifier we want to specify the maximum width
in case an ending \0 is missing.

So slen must be used as precision and not as field width.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>

lib/efi_loader/efi_device_path_to_text.c

@@ -153,7 +153,7 @@ static char *dp_media(char *s, struct efi_device_path *dp)
 		struct efi_device_path_file_path *fp =
 			(struct efi_device_path_file_path *)dp;
 		int slen = (dp->length - sizeof(*dp)) / 2;
-		s += sprintf(s, "/%-*ls", slen, fp->str);
+		s += sprintf(s, "/%-.*ls", slen, fp->str);
 		break;
 	}
 	default: