OMAP: HWMOD: Add support for early device register into omap device layer

This patch adds support in omap device layer to register devices
as early platform devices. Certain devices needed during system boot up
like timers, gpio etc can be registered as early devices. This will
allow for them to be probed very early on during system boot up.
This patch adds a parameter is_early_device in omap_device_build.
Depending on this parameter a call to early_platform_add_devices
or platform_register_device is made.

Signed-off-by: Thara Gopinath <thara@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>