PCI: designware: Remove pci_assign_unassigned_resources() from dw_pcie_host_init()

The pci_common_init_dev() call right before will already handle the device
resource allocation, so this call was a no-op.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Mohit Kumar <mohit.kumar@st.com>