qcacld-3.0: Use mac_handle_t in wlan_hdd_cfg80211

Change "qcacld-3.0: Introduce mac_handle_t" introduced a modern
name for what was previously called the tHalHandle. Transition
wlan_hdd_cfg80211 to use the new naming.

Change-Id: Ia9a7014db052c46ee16d2cb834b46a0b7afafeee
CRs-Fixed: 2267223