mei: Avoid the use of one-element arrays

One-element arrays are being deprecated[1]. Replace the one-element
arrays with a simple value type u8 reserved, once this is just a
placeholder for alignment.

Also, while there, use the preferred form for passing a size of a struct.
The alternative form where struct name is spelled out hurts readability
and introduces an opportunity for a bug when the variable type is changed
but the corresponding sizeof that is passed as argument is not.

[1] https://github.com/KSPP/linux/issues/79

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200714214516.GA1040@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hbm.c

@@ -408,14 +408,14 @@ static int mei_hbm_add_cl_resp(struct mei_device *dev, u8 addr, u8 status)
 {
 	struct mei_msg_hdr mei_hdr;
 	struct hbm_add_client_response resp;
-	const size_t len = sizeof(struct hbm_add_client_response);
+	const size_t len = sizeof(resp);
 	int ret;
 
 	dev_dbg(dev->dev, "adding client response\n");
 
 	mei_hbm_hdr(&mei_hdr, len);
 
-	memset(&resp, 0, sizeof(struct hbm_add_client_response));
+	memset(&resp, 0, len);
 	resp.hbm_cmd = MEI_HBM_ADD_CLIENT_RES_CMD;
 	resp.me_addr = addr;
 	resp.status  = status;

drivers/misc/mei/hw.h

@@ -346,13 +346,13 @@ struct hbm_add_client_request {
  * @hbm_cmd: bus message command header
  * @me_addr: address of the client in ME
  * @status: if HBMS_SUCCESS then the client can now accept connections.
- * @reserved: reserved
+ * @reserved: reserved for alignment.
  */
 struct hbm_add_client_response {
 	u8 hbm_cmd;
 	u8 me_addr;
 	u8 status;
-	u8 reserved[1];
+	u8 reserved;
 } __packed;
 
 /**
@@ -461,7 +461,7 @@ struct hbm_notification {
 	u8 hbm_cmd;
 	u8 me_addr;
 	u8 host_addr;
-	u8 reserved[1];
+	u8 reserved;
 } __packed;
 
 /**