hinic3: Mailbox management interfaces

Add mailbox management interfaces initialization.
It enables mailbox to communicate with event queues from HW.

Co-developed-by: Xin Guo <guoxin09@huawei.com>
Signed-off-by: Xin Guo <guoxin09@huawei.com>
Co-developed-by: Zhu Yikai <zhuyikai1@h-partners.com>
Signed-off-by: Zhu Yikai <zhuyikai1@h-partners.com>
Signed-off-by: Fan Gong <gongfan1@huawei.com>
Link: https://patch.msgid.link/3ce856068d23a0bbce74157e16f701c58ebbb1ce.1755673097.git.zhuyikai1@h-partners.com


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