Since we have generic definitions for bus frequencies, let's use them.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Khalil Blaiech <kblaiech@nvidia.com>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>