An upcoming change will invoke ath12k_mac_init_arvif(),
ath12k_mac_assign_link_vif(), ath12k_mac_unassign_link_vif(), and
ath12k_mac_remove_link_interface() from a line located above their current
definition. Hence, relocate these functions to above so that these can be
invoked later on.
No functionality changes. Compile tested only.
Signed-off-by: Aditya Kumar Singh <aditya.kumar.singh@xxxxxxxxxxxxxxxx>