arm64: dts: apq8016-sbc: Set up LDO2, LDO6 and LDO17 regulator voltage ranges

On the APQ8016 SBC, the LDO2 PM8916 regulator feeds 1.2V to the following:

- VDDA_1P2_MIPI_DSI and VDDA_MIPI_CSI pins on APQ8016.
- VCCCAD pins on the LPDDR3 chip.
- VDDPX_1 pins on APQ8016.

The LDO6 regulator feeds 1.8V to:
- VDAA_MIPI_DSI0_PLL pin on APQ8016.
- QFPROM_BLOW_VDD pin on PM8916.
- The AVDD, A2VDD and DVDD pins on ADV7533 bridge.

The LDO17 regulator feeds 3.3V to:
- The V3P3 pin on ADV7533 bridge.

Currently, the regulator min/max voltages for all the LDOs are set to the
range of what the PMIC supports. Set the ranges for L2, L6 and L17 to what
we need, i.e. 1.2V, 1.8V and 3.3V respectively.

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
(cherry picked from commit 5c99bfdc)
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>