dmaengine: stm32-mdma: Remove redundant initialization of pointer hwdesc

The pointer hwdesc is being initialized with a value that is never
read, it is being updated later in a for-loop. The assignment is
redundant and can be removed.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20211204140032.548066-1-colin.i.king@gmail.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>