soundwire: cadence_master: make use of mclk_freq property

soundwire: cadence_master: make use of mclk_freq property

Now that the prototype and Intel implementation are enabled, use this
property to avoid hard-coded values.

For example for ICL the mclk_freq value is 38.4 MHz while on CNL/CML
it's 24 MHz. The mclk_freq should not be confused with the
max_clk_freq, which si the maximum bus clock. The mclk_freq is
typically tied to the oscillator frequency and does not change between
platforms. The max_clk_freq value is linked to the maximum bandwidth
needed and topology/trace length.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190806005522.22642-13-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>