ASoC: msm: qdsp6v2: check ion alloc return value

The msm_audio_ion_alloc function returns a non zero
value when there is an error. Check this error and return
from the function properly

Change-Id: Ib2c4c08850bce1f59de76a6b60be0b6b10d24dbd
Signed-off-by: Aravind Kumar <akumark@codeaurora.org>