Fix: honor capability bits of legacy J-Link V5 probes

[ALTracer]

Detailed description

Add support for older J-Link V5 adapters to BMDA.
OEM considers these "legacy" https://wiki.segger.com/J-Link_BASE_V5_or_lower , in fact everything pre-V11.
IMO these are still okay for raw sequences and "accelerated bit-banging" of conventional good old JTAG, fixed-direction bus transceivers included.

• This does not look like a new feature.
• Current Blackmagic Hosted App crashes V5 hardware (2008 firmware) adapters (but works with JLink V8 hw 2014 fw)
• This pull request adds a few checks regarding "multiple interfaces" capability bits to keep BMDA+JLink V5 always in JTAG mode.

I tested this on V5.4 and V5.3 yellow "Kickstart" adapters from 2006 and now they at least work. Also tested on V8 (same AT91SAM7S64, more bus transceivers for bidirectional SWD), no regressions, both SWD & JTAG are accessible and working.
Code loosely follows similar checks from openocd+libjaylink, published UM08001 and aims to be a follow-up to #1548.
The firmware in question does not support 0xc7 "EMU_CMD_SELECT_IF" commands at all. I can remove irrelevant parts of in-code comments on request.

Your checklist for this pull request

• I've read the Code of Conduct
• I've read the guidelines for contributing to this repository
• It builds for hardware native (make PROBE_HOST=native) -- not applicable
• It builds as BMDA (make PROBE_HOST=hosted)
• I've tested it to the best of my ability
• My commit messages provide a useful short description of what the commits do

Closing issues

I would open an issue about this back in August, but instead I provide a suggested fix here.

[perigoso]

LGTM, just a note on one bit of code style

[dragonmux]

Patch looks good. Dependant on perigoso's response to the review comment on the jlink_select_interface() change, LGTM to merge.