BridgeOSHardwareModel
This variable is derived from `SecureBootModel` specified in the config (e.g. j137 becomes J137AP) and is used by macOS 12 during updates and installations. Setting this variable allows to use macOS 12 with T2 board identifiers, e.g. j137.
This reverts commit 93c96d030b176873052e479b20e5a7f0f367ce3c.