PCI: iproc: Remove dependency on ARM specific struct pci_sys_data

The iproc driver is using ARM's struct pci_sys_data simply to store a
private data pointer. This is completely unnecessary, so store the
private data directly in bus->sysdata as is done on arm64.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>