clk: renesas: r8a77965: Add 3DGE and ZG support

The 3DGE and ZG clocks are necessary to support the 3D graphics.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/1767d01cfffd7490861f2cf6ad6c0df100916907.1689599217.git.geert+renesas@glider.be