ASoC: omap-twl4030: Fix typo in 2nd dai link's platform_name

The platform_name should be omap-mcasp3 for the 2nd link which is used for
voice connection.

Reported-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie+linaro@kernel.org>
Cc: stable@vger.kernel.org