pci: Rename pci_root_bus_new_inplace() to pci_root_bus_init()

pci: Rename pci_root_bus_new_inplace() to pci_root_bus_init()

Rename the pci_root_bus_new_inplace() function to
pci_root_bus_init(); this brings the bus type in to line with a
"_init for in-place init, _new for allocate-and-return" convention.
To do this we need to rename the implementation-internal function
that was using the pci_root_bus_init() name to
pci_root_bus_internal_init().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 20210923121153.23754-4-peter.maydell@linaro.org