ASoC: amd: fix memory leak of i2s_data on error return

Currently when snd_pcm_hw_constraint_integer fails there is
a memory leak of i2s_data on the error return path. Fix this by
kfree'ing i2s_data before returning.

Detected by CoverityScan, CID#1475479 ("Resource leak")

Fixes: 0b87d6bc ("ASoC: amd: add acp3x pcm driver dma ops")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mark Brown <broonie@kernel.org>