ASoC: fsl_asrc: protect macro argument

Protect macro argument with parentheses to avoid ambiguity.
This fixes a warning seen with clang:
  warning: logical not is only applied to the left hand side of this comparison

Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>