ASoC: fsl: fsl_esai: clarify expression

cppcheck warning:

sound/soc/fsl/fsl_esai.c:307:16: style: Clarify calculation precedence
for '%' and '?'. [clarifyCalculation]
    clk_id % 2 ? "extal" : "fsys");
               ^

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210219232937.6440-5-pierre-louis.bossart@linux.intel.com


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