soundwire: intel: fix factor of two in MCLK handling

Somehow Intel folks were confused, the property is 2x what the mclk
frequency actually is (checked the actual bus frequency with a scope)

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200113231129.19049-1-pierre-louis.bossart@linux.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>