apq8064: display: fix struct type of renesas_pdata and implement pmic_backlight

Change-Id: Ia12ab7d323a6f0e0941b7e5eb744b9e73f10c5da
apq8064: display: make use of regulators for aries

Change-Id: I64cdd668dd04c916e81d2b471bfedea60a57154b