staging: wilc1000: use ARRAY_SIZE macro

This patch uses ARRAY_SIZE macro found by checkpatch.pl

WARNING: Prefer ARRAY_SIZE(wb)
drivers/staging/wilc1000/wilc_spi.c:400
drivers/staging/wilc1000/wilc_spi.c:402

Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>