tcl: Add support for the Numato Lab Mimas A7 board

tcl: Add support for the Numato Lab Mimas A7 board

The Mimas A7 FPGA board has FTDI FT2232 whose channel B is connected to
Artix-7 FPGA's JTAG interface. Hence, OpenOCD can easily interface with
it via the its ftdi driver interface. Tested to be working great up to
30 MHz.

Change-Id: Ieda015fbc6135bf95ad5a069cbf38650da45911e
Signed-off-by: Rohit Singh <rohit91.2008@gmail.com>
Reviewed-on: http://openocd.zylin.com/4720
Tested-by: jenkins
Reviewed-by: Tim "mithro" Ansell <me@mith.ro>
Reviewed-by: Robert Jordens <jordens@gmail.com>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>