This atomic commit changes the Integrator clock implementation
and the machines to register clocks from the device tree and
use these instead of the previous hard-coded clocks.

In the clock implementation all hard-coded clocks and the
special initialization function call goes away, and is
replaced by two compatible strings for the two clocks
available on the core module.

Cc: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>