ARM: dts: am335x-evmsk: Correct the regulators for the audio codec

Correctly map the regulators used by tlv320aic3106.
Both 1.8V and 3.3V for the codec is derived from VBAT via fixed regulators.

Cc: <Stable@vger.kernel.org> # v4.14+
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>