dtc: Use va_end to match corresponding va_start

Although on some systems va_end is a no-op, it is good practice
to use va_end, especially since the manual states:

"Each invocation of va_start() must be matched by a corresponding
invocation of va_end() in the same function."

Signed-off-by: Colin Ian King <colin.king@canonical.com>

checks.c

@@ -113,6 +113,7 @@ static inline void check_msg(struct check *c, const char *fmt, ...)
 		vfprintf(stderr, fmt, ap);
 		fprintf(stderr, "\n");
 	}
+	va_end(ap);
 }
 
 #define FAIL(c, ...) \

util.h

@@ -34,6 +34,7 @@ static inline void __attribute__((noreturn)) die(const char *str, ...)
 	va_start(ap, str);
 	fprintf(stderr, "FATAL ERROR: ");
 	vfprintf(stderr, str, ap);
+	va_end(ap);
 	exit(1);
 }