parallels: make device addressing consistent

parallels: make device addressing consistent

In Parallels we do not support device name hints
aka <target dev=../> option and full-fledged device
disk device addressing through
<address type=.. controller=.. bus=.. target=.. unit=../>
and have only one index instead.
In this situation to be consistent we can only take
one-to-one mapping from some reasonable subset
of full address. Values outside this subset are
invalid to create Parallels VMs.

Reasonable mapping is default one defined in virDomainDiskDefAssignAddress.

Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@parallels.com>