scsi: qla4xxx: Use correct variable in memset for clarity

Both mbox_cmd and mbox_sts have the same size, so using sizeof(mbox_cmd)
when clearing mbox_sts did not cause any functional issue. However, it
is misleading and reduces code readability.

Update the memset() calls to use sizeof(mbox_sts) to make the intent
clear

Signed-off-by: Alok Tiwari <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/qla4xxx/ql4_mbx.c

···
 	uint32_t crash_record_size = 0;
 
 	memset(&mbox_cmd, 0, sizeof(mbox_cmd));
-	memset(&mbox_sts, 0, sizeof(mbox_cmd));
+	memset(&mbox_sts, 0, sizeof(mbox_sts));
 
 	/* Get size of crash record. */
 	mbox_cmd[0] = MBOX_CMD_GET_CRASH_RECORD;
···
 
 	/* Get Crash Record. */
 	memset(&mbox_cmd, 0, sizeof(mbox_cmd));
-	memset(&mbox_sts, 0, sizeof(mbox_cmd));
+	memset(&mbox_sts, 0, sizeof(mbox_sts));
 
 	mbox_cmd[0] = MBOX_CMD_GET_CONN_EVENT_LOG;
 	mbox_cmd[2] = LSDW(event_log_dma);