Fix return code for ssize_t.

The ssize_t must be defined in the range [-1, SSIZE_MAX].

The return value is overwritten to -EINVAL later anyway,
return -1 here to be on the safe side.

Fixes: #900

src/utils_password.c

@@ -99,7 +99,7 @@ static ssize_t read_tty_eol(int fd, char *pass, size_t maxlen)
 	ssize_t r, read_size = 0;
 
 	if (maxlen > SSIZE_MAX)
-		return -EINVAL;
+		return -1;
 
 	do {
 		r = read(fd, pass, maxlen - read_size);