Especially needed when leaving the debugger or during debug unit power-up.
ARM Debug Interface Architecture Specification ADIv5.0 to ADIv5.2
tells to clock the data through SW-DP to either :
- immediate start a new transaction
- continue to drive idle cycles
- or clock at least 8 idle cycles
Implement last option to favour correctness over slight speed decrease
Implement only for adapters where we assemble the seq_out_parity in our code,
as on firmware, ftdi and jlink. Hopefully the high level adapters do it right.
Reverts 2c33cde63fe779d3019fe8f63dd4420cb960bbfe and
cde7726b8730242cd40a9974d129b46af80c68af
bf548e92c0