clk: renesas: Handle E3/D3 RPCSRC clock

The RPCSRC clock divider on R-Car D3 is very similar to the one on R-Car
E3, but uses a different pre-divider for the PLL0 parent.  Add a new
macro to describe it, reusing the existing clock type for R-Car E3.

As both E3/D3 RPCSRC clock divider are different from the rest of R-Car
Gen3, keep the original implementation from Linux.

Based on Linux commit 40745482eec8 ("clk: renesas: r8a774c0: Add RPC
clocks") by Lad Prabhakar and 9d18f81b3535 ("clk: renesas: r8a77995: Add
RPC clocks") by Geert Uytterhoeven.

Signed-off-by: Hai Pham <hai.pham.ud@renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org> # Add D3 tweaks