tap_get_tms_path_len() function

Function int tap_get_tms_path_len returns the total number of bits that represents a TMS path transition as given by the function tap_get_tms_path(). For at least one interface (JLink) it's not OK to simply "pad" TMS sequences to fit a whole byte. (I suspect this is a general TAP problem within OOCD.) Padding TMS causes all manner of instability that's not easily discovered. Using this routine we can apply EXACTLY the state transitions required to make something work - no more - no less.