PCI: rcar: Use devm_pci_alloc_host_bridge()

Move to the resource managed devm_pci_alloc_host_bridge() and simplify
the error path.

Link: https://lore.kernel.org/r/20200722022514.1283916-15-robh@kernel.org


Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-renesas-soc@vger.kernel.org