commonlib: Add assembly optimization for ipchksum() on arm64
This patch adds a bit of optimized assembly code to the ipchksum()
algorithm for arm64 targets in order to take advantage of larger load
sizes and the add-with-carry instruction. This improves execution speed
on a Cortex-A75 by more than 20x.
Change-Id: I9c7bbc9d7a1cd083ced62fe9222592243a796077
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/80254
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Yidi Lin <yidilin@google.com>