kernel: build in CPU routines for SHA-256 and SHA-512

[bcressey]

Issue number:
Fixes #66

Description of changes:
Ensure that support for specialized CPU instructions that accelerate SHA-256 are built into the kernel for both x86_64 and aarch64. Add SHA-512 for good measure since we may switch to that hash algorithm for dm-verity at some point.

Testing done:
aarch64 variants now print:

[    0.166490] device-mapper: verity: sha256 using implementation "sha256-ce"

Tested both aws-k8s-1.32 and aws-k8s-1.32-fips for aarch64.

Kernel config diff:

==> config-aarch64-5.10-diff <==
 CRYPTO_SHA256_ARM64 m -> y
 CRYPTO_SHA2_ARM64_CE m -> y
 CRYPTO_SHA512_ARM64 n -> y
 CRYPTO_SHA512_ARM64_CE n -> y

==> config-aarch64-5.15-diff <==
 CRYPTO_SHA256_ARM64 m -> y
 CRYPTO_SHA2_ARM64_CE m -> y
 CRYPTO_SHA512_ARM64 m -> y
 CRYPTO_SHA512_ARM64_CE m -> y

==> config-aarch64-6.1-diff <==
 CRYPTO_SHA256_ARM64 m -> y
 CRYPTO_SHA2_ARM64_CE m -> y
 CRYPTO_SHA512_ARM64 m -> y
 CRYPTO_SHA512_ARM64_CE m -> y

==> config-x86_64-5.10-diff <==

==> config-x86_64-5.15-diff <==

==> config-x86_64-6.1-diff <==

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.