staging/wilc1000: get rid of WILC_SDIO_IRQ_GPIO

Whether the SDIO function uses an internal or external interrupt
should not be a compiletime decision but be determined at runtime.

This changes the code to pass a GPIO number from the init code
as early as possible, and leaves just one #ifdef WILC_SDIO_IRQ_GPIO
to preserve the previous behavior.

All other locations that check for the interrupt method are turned
into runtime checks based on the gpio number (>=0) or the interrupt
number (>0).

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>