dm: pci: Use driver model PCI API in auto-config

dm: pci: Use driver model PCI API in auto-config

At present we are using legacy functions even in the auto-configuration code
used by driver model. Add a new pci_auto.c version which uses the correct
API.

Create a new pci_internal.h header to hold functions that are used within
the PCI subsystem, but are not exported to other drivers.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>