wifi: ath12k: refactor ath12k_wmi_tlv_parse_alloc()

Since 'ath12k_wmi_tlv_parse_alloc()' always operates on 'skb->data,
skb->len' tuple, it may be simplified to pass the only 'skb' argument
instead (which implies refactoring of 'ath12k_pull_bcn_tx_status_ev()',
'ath12k_pull_chan_info_ev()' and 'ath12k_pull_pdev_temp_ev()' in the
same way). This is an ath12k counterpart of the recently submitted
ath11k patch and compile tested only as well.
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20231219091022.70861-1-dmantipov@yandex.ru