staging: wilc1000: separate hif_sdio and hif_spi into different module

hif_sdio and hif_spi objects are compiled all the time even though one of SPI
or SDIO is selected. This patch separates hif_sdio and hif_spi into different
modules using ifdef define.
After rework SPI and SDIO modules with only one hif interface, the define
WILC_SDIO will be removed. This is first path of this series.

Signed-off-by: Glen Lee <glen.lee@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>