dmaengine: stm32-mdma: use vchan_terminate_vdesc() in .terminate_all

dmaengine: stm32-mdma: use vchan_terminate_vdesc() in .terminate_all

BugLink: https://bugs.launchpad.net/bugs/1900624
[ Upstream commit dfc708812a2acfc0ca56f56233b3c3e7b0d4ffe7 ]

To avoid race with vchan_complete, use the race free way to terminate
running transfer.

Move vdesc->node list_del in stm32_mdma_start_transfer instead of in
stm32_mdma_xfer_end to avoid another race in vchan_dma_desc_free_list.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Link: https://lore.kernel.org/r/20200127085334.13163-7-amelie.delaunay@st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Ian May <ian.may@canonical.com>