[WIP]orangepi3b: add bluetooth support

[amazingfate]

Description

Add node sprd-mtty to mainline devicetree. And add userspace binary hciattach_opi to enable uart bluetooth.

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• Test A
• Test B

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[rpardini]

Cherry picked, built, tested (via bluetoothctl), works.