Add support for Acer Chromebook 515 Plus (CB515-2H) / Google Omnigul Platform

Add support for the Acer Chromebook 515 Plus - CB515-2H, also known as the Google Omnigul / Brya.

lspci output:

00:00.0 Host bridge: Intel Corporation Device 4609 (rev 04)
00:02.0 VGA compatible controller: Intel Corporation Alder Lake-UP3 GT1 [UHD Graphics] (rev 0c)
00:04.0 Signal processing controller: Intel Corporation Alder Lake Innovation Platform Framework Processor Participant (rev 04)
00:08.0 System peripheral: Intel Corporation 12th Gen Core Processor Gaussian & Neural Accelerator (rev 04)
00:0a.0 Signal processing controller: Intel Corporation Platform Monitoring Technology (rev 01)
00:0d.0 USB controller: Intel Corporation Alder Lake-P Thunderbolt 4 USB Controller (rev 04)
00:12.0 Serial controller: Intel Corporation Alder Lake-P Integrated Sensor Hub (rev 01)
00:12.7 Universal Flash Storage controller: Intel Corporation Device 51ff (rev 01)
00:14.0 USB controller: Intel Corporation Alder Lake PCH USB 3.2 xHCI Host Controller (rev 01)
00:14.2 RAM memory: Intel Corporation Alder Lake PCH Shared SRAM (rev 01)
00:14.3 Network controller: Intel Corporation Alder Lake-P PCH CNVi WiFi (rev 01)
00:15.0 Serial bus controller: Intel Corporation Alder Lake PCH Serial IO I2C Controller #0 (rev 01)
00:15.1 Serial bus controller: Intel Corporation Alder Lake PCH Serial IO I2C Controller #1 (rev 01)
00:15.3 Serial bus controller: Intel Corporation Alder Lake PCH Serial IO I2C Controller #3 (rev 01)
00:16.0 Communication controller: Intel Corporation Alder Lake PCH HECI Controller (rev 01)
00:19.0 Serial bus controller: Intel Corporation Alder Lake-P Serial IO I2C Controller #0 (rev 01)
00:19.1 Serial bus controller: Intel Corporation Alder Lake-P Serial IO I2C Controller #1 (rev 01)
00:1e.0 Communication controller: Intel Corporation Alder Lake PCH UART #0 (rev 01)
00:1e.3 Serial bus controller: Intel Corporation Alder Lake SPI Controller (rev 01)
00:1f.0 ISA bridge: Intel Corporation Alder Lake PCH eSPI Controller (rev 01)
00:1f.3 Multimedia audio controller: Intel Corporation Alder Lake PCH-P High Definition Audio Controller (rev 01)
00:1f.5 Serial bus controller: Intel Corporation Alder Lake-P PCH SPI Controller (rev 01)

• Already runs Coreboot
• Intel iGPU "UHD Graphics"
• 12th Gen Intel Core i3-1215U
• Fixed 8 GB RAM
• Fixed 128 GB UFS Storage [00:12.7 in lspci output]
• Intel AX211 Wi-Fi 6E
• 32MB Winbond chip - W25Q256JVEM

Work already being done in https://github.com/linuxboot/heads/pull/1658.

Start by reviewing the Acer Chromebook 515 Plus hardware details and the linked linuxboot/heads pull request #1658, where this support is already being developed. Done would mean the Omnigul/Brya platform is supported by heads; the issue does not identify specific files or tests.