Fix typo (s/dwi-/dw-/) in the directory path.

Fixes: 1fe20f1b ("dmaengine: Introduce DW AXI DMAC driver")
Signed-off-by: Denis Efremov <efremov@linux.com>
Link: https://lore.kernel.org/r/20190813060004.10594-1-efremov@linux.comSigned-off-by: Vinod Koul <vkoul@kernel.org>