ASoC: Intel: Skylake: skl-nhlt: remove redundant initialization

Fix cppcheck warning:

sound/soc/intel/skylake/skl-nhlt.c:203:21: style: Variable 'rate' is
assigned a value that is never used. [unreadVariable]
 unsigned long rate = 0;
                    ^

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200813200147.61990-17-pierre-louis.bossart@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>