ASoC: tas2562: Fix shut-down gpio property

Fix the shut-down gpio property to be shut-down-gpio and fix the
example.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: https://lore.kernel.org/r/20200624174932.9604-2-dmurphy@ti.com


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