qemu_process: Drop needless check in qemuProcessNeedMemoryBackingPath()

qemu_process: Drop needless check in qemuProcessNeedMemoryBackingPath()

The aim of this function is to return whether domain definition
and/or memory device that user intents to hotplug needs a private
path inside cfg->memoryBackingDir. The rule for the memory device
that's being hotplug includes checking whether corresponding
guest NUMA node needs memoryBackingDir. Well, while the rationale
behind makes sense it is not necessary to check for that really -
just a few lines above every guest NUMA node was checked exactly
for that.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>