ASoC: sta32x: fix register range in regmap.

The STA32X_AUTO3 is a writable register that currently does not appear
in the regmap ranges(neither read nor write). By adding this register
to the register ranges there is no gap anymore and the existing
register ranges can be joined. This fixes a regression introduced in
commit a1be4cea where the driver was
moved to direct regmap usage and the STA32X_AUTO3 register was missed.
That made it impossible to choose the preset EQ mode set through the
STA32X_AUTO3 register.

Fixes: a1be4cea (ASoC: sta32x: Convert to direct regmap API usage)
Signed-off-by: Thomas Niederprüm <niederp@physik.uni-kl.de>
Signed-off-by: Mark Brown <broonie@kernel.org>