net: libwx: Add msg task func

Implement wx_msg_task which is used to process mailbox
messages sent by vf.

Signed-off-by: Mengyuan Lou <mengyuanlou@net-swift.com>
Link: https://patch.msgid.link/8257B39B95CDB469+20250408091556.9640-5-mengyuanlou@net-swift.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>