fdt: Add several apis to decode pci device node

This commit adds several APIs to decode PCI device node according to
the Open Firmware PCI bus bindings, including:
- fdtdec_get_pci_addr() for encoded pci address
- fdtdec_get_pci_vendev() for vendor id and device id
- fdtdec_get_pci_bdf() for pci device bdf triplet
- fdtdec_get_pci_bar32() for pci device register bar

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
(Include <pci.h> in fdtdec.h and adjust tegra to fix build error)