ASoC: amd: Removing unnecessary instance initialization

In DMA pointer the initialzation of instance is of no use.
In fact it will reinitialize the instance variable which is already
opened and functional.

Signed-off-by: Ravulapati Vishnu vardhan rao <Vishnuvardhanrao.Ravulapati@amd.com>
Link: https://lore.kernel.org/r/1590652337-21587-1-git-send-email-Vishnuvardhanrao.Ravulapati@amd.com


Signed-off-by: Mark Brown <broonie@kernel.org>