Add CDMA/EVDO support to comgt package

Add CDMA/EVDO support to comgt package

This patch adds a chat script and makes some modifications to
/lib/network/3g.sh to enable seamless use of CDMA/EVDO modems in
addition to the existing GPRS/UMTS support.  Modifications to 3g.sh
are:
 - Added 'chat' variable to point at the appropriate script
 - Added 'evdo' and 'cdma' as acceptable 'service' values, and skip
the whole gcom initialization bit
 - Changed pppd connection speed from 460800 to more widely supported
115200; in my experience, this is not your actual connection speed,
but at what speed pppd sends setup commands to the interface.

This kinda eliminates the need for /etc/ppp/3g.connect - I think I've
replaced that functionality, but in a slightly more standardized
method, using the 'connect' variable understood by PPP.

Signed-off-by: RB<aoz.syn@gmail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@10347 3c298f89-4303-0410-b956-a3cf2f4a3e73