staging: wilc1000: remove unneeded function

wilc_spi_init in linux_wlan_spi.c is unneeded. It just return true. Rename
_wilc_spi_init in wlan_spi.c to wilc_spi_init.

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