dma_ch is being initialized to zero and then immediately afterwards
being updated again, so the first initialization is redundant and
can be remove.

Likewise, the pointer v is being initialized twice, so remove the second
duplicate initialization.

Cleans up two clang build warnings:
warning: Value stored to 'dma_ch' is never read
warning: Value stored to 'v' during its initialization is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mark Brown <broonie@kernel.org>