Fixes pn53x_usb timeout while bulk write.

Thanks to Tredger for reporting.

Fixes issue 223.
Updates ChangeLog
acr122_usb: remove pn53x_idle support. Fixes issue #217
Changelog
acr122_pcsc: fix log category
Add driver-dependent PowerDown
pn53x_idle: call driver-dependent PowerDown & do InRelease first, skip redundant InDeselect
call idle() from driver-dependent close() rather than from nfc_close() as some driver still need to do an ack() before