staging: wilc1000: fix always return 0 error

This patch fixes a bug that return always 0 so it fails every time.

Fixes: c1af9db78950 ("staging: wilc1000: call linux_sdio_init instead of io_init")
Signed-off-by: Glen Lee <glen.lee@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>