linux-imx

ASoC: STI: Fix reader substream pointer set

reader->substream is used in IRQ handler for error case but is never set.
Set value to pcm substream on DAI startup and clean it on dai shutdown.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>