clang-tidy: Suppress warning about unchecked error in logfn macro

clang-tidy complains that we're not checking the result of vfprintf in
logfn().  There's not really anything we can do if this fails here, so just
suppress the error with a cast to void.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

util.c

@@ -57,7 +57,7 @@ void name(const char *format, ...) {					\
 	if (setlogmask(0) & LOG_MASK(LOG_DEBUG) ||			\
 	    setlogmask(0) == LOG_MASK(LOG_EMERG)) {			\
 		va_start(args, format);					\
-		vfprintf(stderr, format, args); 			\
+		(void)vfprintf(stderr, format, args); 			\
 		va_end(args);						\
 		if (format[strlen(format)] != '\n')			\
 			fprintf(stderr, "\n");				\