[Gta04-owner] DTMF tone patch for QtMoko

[Neil Jerram]

Hi Radek,

Currently, within a given call, only the first DTMF tone goes out,
I believe because the GTA04 modem doesn't send any response to AT+VTS,
and so the AT chat gets stuck.  The patch below fixes that by using
QAtChat::send instead of QAtChat::chat.

In theory, though, it might interact badly with any other AT commands in
the call, if one of those happens to be in progress at the same time the
user presses a keypad key.  The main example I can think of, that might
be affected, is the CLCC polling.

Bearing that in mind, what do you think?  I guess I could add a new
method QAtChat method