arm64 suport

[Khaled El Mously]

[Impact]
No support for arm64 currently

[Fix]
Add arm64 support, including hardware support patches

[Test]
Confirm that it boots on desired arm64 hardware, as well as VMs

[Regression Potential]
This was never working on arm64 so there should be no risk of regression.
The requested changes included some refactorings of early memory initialization code (all arches) so this presents a small risk. The changes were tested on arm64 as well amd64.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux-gcp - 5.15.0-1002.5

---------------
linux-gcp (5.15.0-1002.5) jammy; urgency=medium

  * jammy/linux-gcp: 5.15.0-1002.5 -proposed tracker (LP: #1965077)

  * arm64 suport (LP: #1965075)
    - [packaging] arm64 bringup
    - [config] Import arm64 config from master and update-configs
    - [packaging] update annotations for arm64

 -- Khalid Elmously <email address hidden> Tue, 15 Mar 2022 23:44:47 -0400

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-gcp-5.15/5.15.0-1005.8~20.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!