Transceiver.cpp: use pointer arithmetics for CMD parsing

It looks like the author of control command parsing code was not
familar with simple pointer arithmetics, so excessive amount of
memory and useless memcopying was used to parse a single command.

Let's introduce two pointers, one of which will point to the
beginning of a command, another to the beginning of its arguments.
Also, let's simplify the command matching by using a separate
function called 'MATCH_CMD'.

Change-Id: I226ca0771e63228cf5e04ef9766057d4107fdd11
1 file changed