staging: wilc1000: refactor interrupt handling for sdio

Make use of FIELD_PREP/FIELD_GET macro to refactor the interrupt
handling for SDIO.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Link: https://lore.kernel.org/r/20200214172250.13026-4-ajay.kathat@microchip.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>