ossl: Move arm_arch.h to a common subdirectory

[markj]

Summary

OpenSSL itself keeps only a single copy of this header. Do the same in
sys/crypto/openssl to avoid the extra maintenance burden. This requires
adjusting the include paths for generated asm files.

No functional change intended.

Reported by: jrtc27

Test Plan

buildworld+buildkernel for arm and arm64

[andrew]

Do we need to update make buildasm in secure/lib/libcrypto? It updates arm_arch.h from the imported OpenSSL.

[markj]

Fix the arm64 buildasm target, have buildasm update arm_arch.h for arm as well

[markj]

In D42866#977720, @andrew wrote:

Do we need to update make buildasm in secure/lib/libcrypto? It updates arm_arch.h from the imported OpenSSL.

Yes, thanks.

[jhb]

I would perhaps be tempted to leave the header in arm/ and have aarch64 include it from there. It is true that upstream doesn't have it in a subdirectory, but upstream doesn't use platform-specific subdirectories for its assembly files at all.

[markj]

In D42866#977839, @jhb wrote:

I would perhaps be tempted to leave the header in arm/ and have aarch64 include it from there. It is true that upstream doesn't have it in a subdirectory, but upstream doesn't use platform-specific subdirectories for its assembly files at all.

I don't have a strong feeling either way. One weak argument for doing it this way: when it comes time to remove 32-bit arm support from the tree, whenever that is, the person doing it won't have to fixup ossl/aarch64.