(update_intr_masks might not need to be done in 3.X, but the new generic
interrupt code is incomplete w/regard to support for the PCCARD code, so
to avoid any potential problems use it. It can't hurt).
- Correctly register pcic_imask with the system interrupt code.
- Call update_intr_masks() so that pcic_imask modifications that occur
when card interrupts are registered get updated in the system
interrupt code.