Enable ixl device on PowerPC64

[luporl]

Summary

With D23975, ixl driver now works on PowerPC64 and may be compiled in-kernel and as a module.

[erj]

The driver is only intended to work on amd64; I can accept PowerPC64 but we don't want to support this driver on 32-bit architectures.

[luporl]

• Make ixl device available only on amd64 and PowerPC64
• Enable ixl by default on PowerPC64

[luporl]

In D23974#527044, @erj wrote:

The driver is only intended to work on amd64; I can accept PowerPC64 but we don't want to support this driver on 32-bit architectures.

Ok, enabling it only on PowerPC64 is fine with me.

[alfredo]

Looks good to me. Nice job fixing it in powerpc64!

[erj]

I'm generally okay with this, but with the caveat that we can't test to make sure any future changes we make will work on anything other than amd64.

[luporl]

In D23974#528509, @erj wrote:

I'm generally okay with this, but with the caveat that we can't test to make sure any future changes we make will work on anything other than amd64.

Ok, I understand. We have a PowerPC64 machine with a X710 NIC that is now using this driver and that some PPC developers will be using, so hopefully we'll be able to test the driver and report/fix issues and regressions, although we use only basic networking functionality.