Staging: ipack/bridges/tpci200: Cleanup in tpci200_slot_irq() and tpci200_interrupt()

Minor cleanup.  No functional changes.

Signed-off-by: Jens Taprogge <jens.taprogge@taprogge.org>
Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>