Merge "Documentation: dt: fb: list mdss pll driver compatible strings"

HDMI and edp.

Required properties:

- compatible:		Compatible name used in the driver

- compatible:		Compatible name used in the driver. Should be one of:

			"qcom,mdss_dsi_pll_8916", "qcom,mdss_dsi_pll_8939",

			"qcom,mdss_dsi_pll_8974", "qcom,mdss_dsi_pll_8994",

			"qcom,mdss_dsi_pll_8994", "qcom,mdss_hdmi_pll"

- cell-index:		Specifies the controller used

- reg:			offset and length of the register set for the device.

- reg-names :		names to refer to register sets related to this device

Example:

	mdss_dsi0_pll: qcom,mdss_dsi_pll@fd922A00 {

		compatible = "qcom,mdss_dsi_pll";

		compatible = "qcom,mdss_dsi_pll_8974";

		label = "MDSS DSI 0 PLL";

		cell-index = <0>;