Re: [libvirt] [PATCH v2 1/5] qemu: change the logic of setting default USB controller

The issue with original code is that the if else-if else condition is not consistent.   The first if checks S390 and address type together, however the second else-if checks only for PPC64, the capability checks are inside that block.   So if arch is S390 but the address type is different from VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE it continues to the last else block and sets the model to piix3-uhci it it's available.   The second else-if for PPC64 doesn't fallback to piix3-uhci it the architecture is PPC64 but none of the capabilities from that block are set.   This patch changes the logic and also makes the if else-if more clearer so the first check is only for architecture and after that in each block we test for capabilities.