clk: renesas: r8a779g0: Add watchdog clock

Add the module clock used by the RCLK Watchdog Timer on the Renesas
R-Car V4H (R8A779G0) SoC.

Extracted from a larger patch in the BSP by Kazuya Mizuguchi.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/a012e4449b976efbeaabebb983fa6cfc1b9329d3.1662714852.git.geert+renesas@glider.be

drivers/clk/renesas/r8a779g0-cpg-mssr.c

@@ -154,6 +154,7 @@ static const struct mssr_mod_clk r8a779g0_mod_clks[] __initconst = {
 	DEF_MOD("hscif1",	515,	R8A779G0_CLK_S0D3_PER),
 	DEF_MOD("hscif2",	516,	R8A779G0_CLK_S0D3_PER),
 	DEF_MOD("hscif3",	517,	R8A779G0_CLK_S0D3_PER),
+	DEF_MOD("wdt1:wdt0",	907,	R8A779G0_CLK_R),
 };
 
 /*