arm/dts: Add tps65910 regulator DT data to am335x-evm.dts

Add tps65910 regulator device tree data to AM335x-EVM by adding
regulator consumers with tightened constraints and regulator-name.
TPS65910 regulator handle can be obtained by using this regulator
name.

This patch also add I2C node with I2C frequency and tps65910 PMIC
I2C slave address.

Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>