ARM: 7648/1: pci: Allow passing per-controller private data

In order to allow drivers to specify private data for each controller,
this commit adds a private_data field to the struct hw_pci. This field
is an array of nr_controllers pointers that will be used to initialize
the private_data field of the corresponding controller's pci_sys_data
structure.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>