ARM: dts: da850-lcdk: Correct the audio codec regulators

Add the board level fixed regulators for 3.3V and 1.8V which is used to
power - among other things - the tlv320aic3106 codec.

Apart from removing the following warning during boot:
tlv320aic3x-codec 0-0018: Invalid supply voltage(s) AVDD: -22, DVDD: -22

With the correct voltages the driver can select correct OCMV value to
reduce pop noise.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>