qcacmn: Check param_buf->hal_reg_caps before dereferencing it

While handling the WMI_SERVICE_READY_EXT_EVENTID WMI FW event, a NULL
pointer dereference can occur if param_buf->hal_reg_caps is not checked.

Check param_buf->hal_reg_caps before dereferencing it to avoid NULL
pointer dereference.

Change-Id: I00eba5e89fbdde78979d19f492df5ad4dca8b80c
CRs-Fixed: 2347673

wmi/src/wmi_unified_tlv.c

@@ -9379,6 +9379,9 @@ static QDF_STATUS extract_reg_cap_service_ready_ext_tlv(
 	if (phy_idx >= reg_caps->num_phy)
 		return QDF_STATUS_E_INVAL;
 
+	if (!param_buf->hal_reg_caps)
+		return QDF_STATUS_E_INVAL;
+
 	ext_reg_cap = &param_buf->hal_reg_caps[phy_idx];
 
 	param->phy_id = ext_reg_cap->phy_id;