pia35x: reduce code duplication for pia-io

- unify setup and teardown functions for io expanders

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
pia35x: pia-wireless: spidev driver init for rfid

- RFID module on pia-wireless is controlled from userspace via spidev1.0

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>