ASoC: fsl_esai: Fix missing break in switch statement

case ESAI_HCKT_EXTAL and case ESAI_HCKR_EXTAL should be
independent of each other, so replace fall-through with break.

Fixes: 43d24e76 ("ASoC: fsl_esai: Add ESAI CPU DAI driver")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>