qcacld-3.0: Clean up the wlan_hdd_softap_tx_rx API

Clean up issues identified in wlan_hdd_softap_tx_rx.h:
- Make sure all APIs have documentation
- Make sure only public APIs are present
- Make sure API identifiers do not use camelCase
- Remove obsolete API hdd_softap_rx_mul_packet_cbk()

Change-Id: Icacd2c7b1358cd6f71d86dc5d8a966973ff7a110
CRs-Fixed: 2275265
2 files changed