i2c: i2c-qcom-geni: Modify the DMA buffer mapping

Modify the DMA buffer mapping to use the wrapper device and using the API
exposed by the geni wrapper file.

Change-Id: I78490191b69ba5a2d1111b5e0ea926204901b961
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>