qemu_domain: add a PPC64 memLockLimit helper
qemu_domain: add a PPC64 memLockLimit helper

There is a lot of documentation in the comments about how PPC64 handles
passthrough VFIO devices to calculate the @memLockLimit. And more will
be added with the PPC64 NVLink2 support code.

Let's remove the PPC64 code from qemuDomainGetMemLockLimitBytes()
body and put it into a helper function. This will simplify the
flow of qemuDomainGetMemLockLimitBytes() that handles all the other
platforms and improves readability of the PPC64 specifics.

Signed-off-by: Daniel Henrique Barboza <627b089ad62deae9aaf06ccfa2c9056df28927e0@gmail.com>
Reviewed-by: Erik Skultety <2c14d38fa47c8799f1b9c16280abe27f8edfec6e@redhat.com>

nertpinx/libvirt,jardasgit/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,eskultety/libvirt,eskultety/libvirt,eskultety/libvirt,crobinso/libvirt,crobinso/libvirt,libvirt/libvirt,jfehlig/libvirt,nertpinx/libvirt,libvirt/libvirt,eskultety/libvirt,andreabolognani/libvirt,nertpinx/libvirt,zippy2/libvirt,jardasgit/libvirt,andreabolognani/libvirt,olafhering/libvirt,olafhering/libvirt,zippy2/libvirt,jfehlig/libvirt,jardasgit/libvirt,crobinso/libvirt,andreabolognani/libvirt,zippy2/libvirt,jardasgit/libvirt,andreabolognani/libvirt,jardasgit/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,crobinso/libvirt,jfehlig/libvirt,eskultety/libvirt,olafhering/libvirt,zippy2/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,libvirt/libvirt,olafhering/libvirt,fabianfreyer/libvirt,libvirt/libvirt