[Meego-kernel] try 2: trace/sink (PTI) for modem debug routing

[james_p_freyensee at linux.intel.com]

Modem trace capture solution for mobile platforms.

This gives the ability to capture modem trace data on multiple MID 
platforms that do not necessarily have PTI HW on the platform.  
It allows the ability to route modem trace data from one tty 
(where the modem trace debug data is coming) to another tty 
(output port) for later analysis in lab or on a product in the field.
Since these are line discipline drivers, it relies on a userspace
application to configure the drivers to the desired tty ports.
    
This is the 2nd submission/review for Meego 1.1.  This patch has tried to address
all concerns that were raised related to locking, how many tty port access per SW
entity, and debug messages.