ASoC: Rename mid-x86 directory to intel

We have other Intel platforms coming having the Smart Sound Technology (SST)
so rename the mid-x86 directory to intel as originally directory name
reflected only Intel MID platform.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>