wifi: ath11k: add WMI event debug messages

Add a debug message for every WMI event to make it easier track what's
happening in WMI. For better readability start every debug message with
"event".

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.23

Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230609142440.24643-5-kvalo@kernel.org