If the PCI controller wasn't configured or enabled delete from the
device tree (include its alias).

For the case that we didn't even configure u-boot with knowledge of
the controller we can use the fact that the pci_controller pointer
is NULL to delete the node in the device tree.  We determine that
a controller was not setup (because of HW config) based on the fact
that cfg_addr wasn't setup.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>