Changed the reported SNR from unsigned to signed.

[EnsilicaEdd]

The rx metadata API returns the SNR of the received data. It's logically a signed value (since LoRa allows the signal to be below the noise floor, the SNR may be negative), and is signed within the stack.
But as it makes its way up the reporting chain, it becomes unsigned. I suspect this is not intentional, so I have simply changed the unsigned type to signed.

Aside: This is an unsolicited Pull Request without an associated Issue. I don't know whether this is acceptable etiquette, so please let me know if not.

Pull request type

[X] Fix
[ ] Refactor
[ ] Target update
[ ] Functionality change
[ ] Breaking change

[hasnainvirk]

Awesome. Looks good.

[hasnainvirk]

@cmonr needs CI here. Minor change, should get in as fast as possible.

[0xc0170]

@EnsilicaEdd Thanks for the fix. We will start CI once we complete 5.10.1 release (within a day).

[cmonr]

Aside: This is an unsolicited Pull Request without an associated Issue. I don't know whether this is acceptable etiquette, so please let me know if not.

@EnsilicaEdd If there's a verified issue, PRs tend to get more attention, but submitting a PR without one is fine.

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 3148
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/8034/

Triggering tests

/morph test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2754
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/8034/

[cmonr]

/morph mbed2-build

[mbed-ci]

Test : SUCCESS

Build number : 2952
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/8034/2952