net: wangxun: Rename private structure in libwx

In order to move the total members in struct adapter to struct wx_hw
to keep the code clean, it's a bad name of 'wx_hw' only for hardware.
Rename 'wx_hw' to 'wx', and rename the pointers at use.

Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>