staging: wilc1000: rename hardwareProductVersion in struct wilc_mac_cfg

This patch renames hardwareProductVersion to hw_product_version to avoid
camelcase.

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