ARM: Split out ARMv7 code and make it possible to have other arch versions.

We don't always want to use ARMv7 code when building for ARM, so we should
separate out the ARMv7 code so it can be excluded, and also make it possible
to include code for some other version of the architecture instead, all per
build component for cases where we need more than one architecture version
at a time.

The tegra124 bootblock will ultimately need to be ARMv4, but until we have
some ARMv4 code to switch over to we can leave it set to ARMv7.

TEST=Built for link, falco, pit, snow, and nyan. Built into the bootblock on

Change-Id: Ia982c91057fac9c252397b7c866224f103761cc7
Reviewed-by: Gabe Black <>
Tested-by: Gabe Black <>
Commit-Queue: Gabe Black <>
19 files changed