ARM: OMAP2+: Drop legacy platform data for dra7 mpu

We can now probe devices with ti-sysc interconnect driver and dts data.
Let's drop the related platform data and custom ti,hwmods dts property.

As we're just dropping data, and the early platform data init is based on
the custom ti,hwmods property, we want to drop both the platform data and
ti,hwmods property in a single patch.

Signed-off-by: Tony Lindgren <tony@atomide.com>