dmaengine: dw-axi-dmac: Fix uninitialized variable in axi_chan_block_xfer_start()

dmaengine: dw-axi-dmac: Fix uninitialized variable in axi_chan_block_xfer_start()

Coverity complains of an uninitialized variable:

5. uninit_use_in_call: Using uninitialized value config.dst_per when calling axi_chan_config_write. [show details]
6. uninit_use_in_call: Using uninitialized value config.hs_sel_src when calling axi_chan_config_write. [show details]
CID 121164 (#1-3 of 3): Uninitialized scalar variable (UNINIT)
7. uninit_use_in_call: Using uninitialized value config.src_per when calling axi_chan_config_write. [show details]
418        axi_chan_config_write(chan, &config);

Fix this by initializing the structure to 0 which should at least be benign in axi_chan_config_write(). Also fix
what looks like a cut-n-paste error when initializing config.hs_sel_dst.

Fixes: 824351668a413 ("dmaengine: dw-axi-dmac: support DMAX_NUM_CHANNELS > 8")
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: dmaengine@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Link: https://lore.kernel.org/r/20211025181656.31658-1-tim.gardner@canonical.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>