staging: wfx: drop useless union hif_privacy_key_data

The union hif_privacy_key_data is never used in the driver. So, it is
not necessary to declare it separately from hif_req_add_key.
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200907101521.66082-23-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/hif_api_cmd.h

@@ -500,7 +500,13 @@ struct hif_igtk_group_key {
 	u8     ipn[HIF_API_IPN_SIZE];
 } __packed;
 
-union hif_privacy_key_data {
+struct hif_req_add_key {
+	u8     type;
+	u8     entry_index;
+	u8     int_id:2;
+	u8     reserved1:6;
+	u8     reserved2;
+	union {
 		struct hif_wep_pairwise_key  wep_pairwise_key;
 		struct hif_wep_group_key     wep_group_key;
 		struct hif_tkip_pairwise_key tkip_pairwise_key;
@@ -510,15 +516,7 @@ union hif_privacy_key_data {
 		struct hif_wapi_pairwise_key wapi_pairwise_key;
 		struct hif_wapi_group_key    wapi_group_key;
 		struct hif_igtk_group_key    igtk_group_key;
-};
-
-struct hif_req_add_key {
-	u8     type;
-	u8     entry_index;
-	u8     int_id:2;
-	u8     reserved1:6;
-	u8     reserved2;
-	union hif_privacy_key_data key;
+	} key;
 } __packed;
 
 struct hif_cnf_add_key {