PCI: Unify pcie_find_root_port() and pci_find_pcie_root_port()

PCI: Unify pcie_find_root_port() and pci_find_pcie_root_port()

Previously we used pcie_find_root_port() to find a Root Port from a PCIe
device and pci_find_pcie_root_port() to find a Root Port from a
Conventional PCI device.

Unify the two functions and use pcie_find_root_port() to find a Root Port
from either a Conventional PCI device or a PCIe device.  Then there is no
need to distinguish the type of the device.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Yicong Yang <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Acked-by: Kalle Valo <[email protected]> # wireless
Acked-by: Mika Westerberg <[email protected]> # thunderbolt