pciehp: remove redundant pci_dev initialization

Remove the redundant initialization of pci_dev member of struct
controller in pciehp_probe(). It is initialized in pcie_init().

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>