of/unittest: Add empty dma-ranges address translation tests

Intermediate DT PCI nodes dynamically generated by enabling
CONFIG_PCI_DYNAMIC_OF_NODES have empty dma-ranges property. PCI address
specifiers have 3 cells and when dma-ranges is missing or empty,
of_translate_one() is currently dropping the flag portion of PCI addresses
which are subnodes of the aforementioned ones, failing the translation.
Add new tests covering this case.

With this test, we get 1 new failure which is fixed in subsequent
commit:

FAIL of_unittest_pci_empty_dma_ranges():1245 for_each_of_pci_range wrong CPU addr (ffffffffffffffff) on node /testcase-data/address-tests2/pcie@d1070000/pci@0,0/dev@0,0/local-bus@0

Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
Link: https://lore.kernel.org/r/08f8fee4fdc0379240fda2f4a0e6f11ebf9647a8.1732441813.git.andrea.porta@suse.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>