ASoC: sgtl5000: Fix definition of VAG Ramp Control

ASoC: sgtl5000: Fix definition of VAG Ramp Control

SGTL5000_SMALL_POP is a bit mask, not a value. Usage of
correct definition makes device probing code more clear.

Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Reviewed-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Igor Opaniuk <igor.opaniuk@toradex.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20190719100524.23300-4-oleksandr.suvorov@toradex.com
Signed-off-by: Mark Brown <broonie@kernel.org>