PCI: tegra: Use new pci_register_host_bridge() interface

Tegra is one of the remaining platforms that still use the traditional
pci_common_init_dev() interface for probing PCI host bridges.

This demonstrates how to convert it to the pci_register_host interface I
just added in a previous patch. This leads to a more linear probe sequence
that can handle errors better because we avoid callbacks into the driver,
and it makes the driver architecture independent.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>