staging/wilc1000: turn enable_irq/disable_irq into callbacks

As a preparation for turning the SDIO side of wilc1000 into a separate
module, this removes the last direct caller from the core module into
the sdio specific portion. All calls to wilc_sdio_enable_interrupt()
and wilc_sdio_disable_interrupt() now go through a function pointer
in wilc_hif_func. We also change arguments slightly to pass the device,
as we are already touching those lines and the change will be needed
later to remove the global variables.

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