[ Upstream commit 3c9d3f1b ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>