ARM: 7082/1: platform_device: pdev_archdata: add omap_device pointer

Add omap_device pointer to the ARM-specific arch data in the
platform_device.  This will be used to attach OMAP-specific
device-data to the platform device with device lifetime.

Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>