Presently suspend/resume and migration aren't supported on Xen/!x86. As
such these functions won't be invoked. While merely 4 functions, this
does shrink the resultant kernel.
I'm now unsure of this. Originally this had been disabling x86-only functionality on other architectures, but the D30598 and D30599 make the current form of these functions build on other architectures. As such there is no longer an urgent need to disable them on other architectures, but they simply don't accomplish anything on non-x86.