qcacld-3.0: Add fallthrough comment in hdd_stop_adapter()

In hdd_stop_adapter() there is a switch statement where the logic for
case QDF_SAP_MODE falls through to the next case. Add a fallthrough
comment to explicitly document that this is the desired behavior as
opposed to a missing break statement.

Change-Id: I2fc7b2eeb07eb91b57d5008e74267667a5995c6e
CRs-Fixed: 2233181

core/hdd/src/wlan_hdd_main.c

@@ -5019,6 +5019,7 @@ QDF_STATUS hdd_stop_adapter(struct hdd_context *hdd_ctx,
 							eUPDATE_IE_ALL);
 		ucfg_ipa_flush(hdd_ctx->hdd_pdev);
 		cds_flush_work(&hdd_ctx->sap_pre_cac_work);
+		/* fallthrough */
 
 	case QDF_P2P_GO_MODE:
 		if (QDF_SAP_MODE == adapter->device_mode) {