PCI: rcar: Remove unused pci_sys_data struct from pcie-rcar

The pci_sys_data struct was previously used by pci_common_init_dev() and by
the ARM pcibios_align_resource(), but recent commits removed those uses:

  cbce7900 ("PCI: designware: Make driver arch-agnostic")
  b3a72384 ("ARM/PCI: Replace pci_sys_data->align_resource with global function pointer")

cbce7900 removed the use of pci_common_init_dev() by DesignWare
drivers, including pcie-rcar.c, and b3a72384

 removed the use of struct
pci_sys_data by the ARM pcibios_align_resource().

Remove struct pci_sys_data from pcie-rcar.c.

[bhelgaas: changelog]
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>