ASoC: tlv320aic32x4: Fix regmap range_min

range_min is the lowest address in the virtual register range. This is
the first register with address 0, not the first register of page 1.

Currently all writes to page 1 are mapped to page 0, so the codec fails
to operate.

Fixes: 4d208ca4 (ASoC: tlv320aic32x4: Convert to direct regmap API usage)
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org (v3.13 if the fix misses -final)