csitool: Add bcast_tx_rate parameter

Similar to monitor_tx_rate, this parameter sets the data rate and
antenna(s) used when transmitting broadcast frames.

Signed-off-by: David Ward <david.ward@ll.mit.edu>
csitool: Use connector ID from out-of-tree range

This allows the iwlwifi module to be rebuilt for an existing kernel
and installed in the module 'updates' directory, without needing to
rebuild and install the entire kernel.

Signed-off-by: David Ward <david.ward@ll.mit.edu>