This fixes a CFI failure in callback assignment.
Currently, the callbacks in scheduler_msg are void function
pointers. Update them to have a defined type as
scheduler_msg_process_fn_t to catch type mismatch during
compilation.
Other changes to conform to this new type include:
1. Cast callback to qdf_mc_timer_callback_t when
referencing, and back when assigning
2. Cast wlan_serialization_generic_timer_cb to
take fit into scheduler_msg
3. Cast target_if_vdev_mgr_rsp_timer_cb to fit
into scheduler_msg
Change-Id: I052bc54826d377ae92f5bcc80ca08afb6f5e01e3
CRs-fixed: 2719975
a86b23ee68