ASoC: mfld_machine: Fix compile error

Fixes: 115f3f8 ("ASoC: mfld_machine: Convert to table based DAPM and control setup")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>