C6X: general SoC support

This patch provides a soc_ops struct which provides hooks for SoC functionality
which doesn't fit well into other places.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>