ASoC: tas2770: Remove unneeded read of the TDM_CFG3 register

Remove the unneeded and incorrect read of the TDM_CFG3 register.
The read is done but the value is never used.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: https://lore.kernel.org/r/20191007171157.17813-2-dmurphy@ti.com


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