bfsb: Disable all banks before enabling the one we want, to avoid having two enabled at the same time (eg, when switching from bank 3 to bank 2)
Merge commit 'c86ea19' into bfgminer-3.10.x
Bugfix: Avoid setting tv_idle before testing pool (it will be set if the test fails)
Merge commit '01d9044' into bfgminer-3.10.x