util: Drop virPCIGetAddrString()

util: Drop virPCIGetAddrString()

There's a single user for it which takes an existing
virPCIDeviceAddress, passes its various bits to the
function which in turn constructs a virPCIDevice and
then copies the string representation for the caller
to use: we can use virPCIDeviceAddressAsString()
instead and avoid creating the virPCIDevice in the
first place. Since the function ends up having no
users after the change, we can just drop it.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>