bugfix: Resolve noisy data

[Davidhanson90]

I am creating this PR on behalf of David Whitaker who looked into an issue with noisy data. His comments from his facebook post

Hi, I am delighted to say, I have FIXED the noisy data from sofar2mqtt.  I know many did this project and were disappointed with the data spikes.  Several suggestions about shielding and grounding, but with a CRC errors at the physical layer should never get delivered.
The first error in the .ino sketch has been noted before
  return (received_crc = calculated_crc);
should be 
  return (received_crc == calculated_crc);
The second took a little longer (2 weeks!)
Around line 380
    for(l = 0; l < sizeof(mqtt_status_reads)/sizeof(struct mqtt_status_register); l++)
        addStateInfo(state, mqtt_status_reads[l].regnum, mqtt_status_reads[l].mqtt_name);
Should be 
    for(l = 0; l < sizeof(mqtt_status_reads)/sizeof(struct mqtt_status_register); l++)
        if(addStateInfo(state, mqtt_status_reads[l].regnum, mqtt_status_reads[l].mqtt_name))
        {
            Serial.println("Error from addStateInfo");
            return;
        }
Error status was passed up 4 levels but then ignored when it mattered.
Its now running error free for 4 days.  If anyone else can replicate this fix please let me know.
Edit:- if its replicated a couple of times, then I will try to at least raise a case on Github highlighting the error so others can fix it even if the author does not amend the code.

This is for your consideration.