i40e: Remove unused function declarations

Commit f62b5060 ("i40e: fix mac address checking") left behind
i40e_validate_mac_addr() declaration.
Also the other declarations are declared but never implemented in
commit 56a62fc8 ("i40e: init code and hardware support").

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230804125525.20244-1-yuehaibing@huawei.com


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