clk: renesas: Add r8a774c0 CPG Core Clock Definitions

Add all RZ/G2E (a.k.a. R8A774C0) Clock Pulse Generator Core
Clock Outputs, as listed in Table 8.2g ("List of Clocks
[RZ/G2E]") of the RZ/G2 Hardware User's Manual.

Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>