MLK-24958-1 clk: imx8qxp/dxl: Add clock support for LCDIF

MLK-24958-1 clk: imx8qxp/dxl: Add clock support for LCDIF

Add relevant clocks tree for LCDIF. According to design, LCDIF has
a slice and a dedicated eLCDIF PLL for pixel clock.
On iMX8QXP, there is pixel link mux which is muxed with LCDIF IOs.
It uses slice bypass reference clock for pix clock input.

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
(cherry picked from commit c189dad00743c7a3fcd80d716498289fa7cb2c40)
(cherry picked from commit 5159b4985a84be4f7a06dc8edc63e59658ca4809)