ixl(4): Enable building driver on ARM64

[kgalazka]

Summary

For consistency with other drivers enable building ixl
on ARM64 target.

Please be advised that it is only compile tested.
Intel will continue to test Ethernet drivers only on x86-64
platforms, and is not going to provide support for issues,
which cannot be reproduced in such environment.

Signed-off-by: Krzysztof Galazka <[e-mail]>

Suggested-by: Dave Cottlehuber <[e-mail]>
Sponsored by: Intel Corporation

[manu]

Maybe start with enabling the module for arm64 ?
It's unlikely that anyone will test adding the driver to their kernel config if they didn't tested with the module before.
Also I don't see why anyone would want the driver in the kernel if a module exists.