ARM: OMAP2+: Remove omap4 ocp2scp pdata

This is omap4+ only and no longer needed as omap4+ can be booted
using device tree.

Also remove the related pdata handling from the driver and the
now unneeded platform_data/omap_ocp2scp.h.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
Reviewed-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>