Add introductions on how to enable Vector FM10K Rx/Tx functions,
the preconditions and assumptions on Rx/Tx configuration parameters.
The new content also lists the limitations of vector, so app/customer
can do better to select best Rx/Tx functions.
Signed-off-by: Chen Jing D(Mark) <jing.d.chen@intel.com>
Acked-by: John McNamara <john.mcnamara@intel.com>