qcacld-3.0: Use mac_handle_t in wlan_hdd_cfg

Change "qcacld-3.0: Introduce mac_handle_t" introduced a modern
name for what was previously called the tHalHandle. Transition
wlan_hdd_cfg to use the new naming.

Change-Id: Ib3a9d26cb8966b52b71e97d7b9fb8f2cca9ed916
CRs-Fixed: 2266499