C6X: clocks

The C6X SoCs contain several PLL controllers each with up to 16 clock outputs
feeding into the cores or peripheral clock domains. The hardware is very similar
to arm/mach-davinci clocks. This is still a work in progress which needs to be
updated once device tree clock binding changes shake out.

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