ARM: dts: da850-evm: 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: Too high supply voltage(s) AVDD: 5000000, DVDD: 5000000

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>