Bump Gecko SDK to 4.3.1

[puddly]

https://github.com/SiliconLabs/gecko_sdk/releases/tag/v4.3.1

Relevant release notes:

• https://www.silabs.com/documents/public/release-notes/emberznet-release-notes-7.3.1.0.pdf
• https://www.silabs.com/documents/public/release-notes/open-thread-release-notes-2.3.1.0.pdf

[darkxst]

slc is currently broken, needs temporary patch until next upstream release. https://github.com/darkxst/silabs-firmware-builder/commit/a2dcffbd0b32fba6276ce61d1e93949730d2e246

[agners]

slc is currently broken, needs temporary patch until next upstream release. darkxst@a2dcffb

Right, I had to work around that in the add-on as well: https://github.com/home-assistant/addons/commit/0fbc10482a6505850364b3a4c75cada5638f110d#diff-e74a157aeb65f06bb177c064c81278d6e92fa7699499d263e96d5d4954fc53fa

I really wish SiLabs would offer versioned downloads for the SLC CLI, I've asked for it in their community forum. Let's see: https://community.silabs.com/s/feed/0D58Y0000AQxX0ZSQV?language=en_US

[agners]

I've pushed the mentioned commit to the branch before merging (see https://github.com/puddly/silabs-firmware-builder/tree/puddly/gsdk-v4.3.1). Yet GitHub didn't pick it up? :thinking: GitHub acts weird sometimes, lately :cry: