clk: renesas: r8a779a0: Fix parent of CBFUSA clock

According to Figure 8.1.1 ("Block Diagram of CPG (R-Car V3U-AD)") in the
R-Car V3U Series User's Manual Rev. 0.5, the parent of the CBFUSA clock
is EXTAL.

Fixes: 17bcc8035d ("clk: renesas: cpg-mssr: Add support for R-Car V3U")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20201019120614.22149-3-geert+renesas@glider.be

drivers/clk/renesas/r8a779a0-cpg-mssr.c

@@ -136,7 +136,7 @@ static const struct cpg_core_clk r8a779a0_core_clks[] __initconst = {
 	DEF_FIXED("icu",	R8A779A0_CLK_ICU,	CLK_PLL5_DIV4,	2, 1),
 	DEF_FIXED("icud2",	R8A779A0_CLK_ICUD2,	CLK_PLL5_DIV4,	4, 1),
 	DEF_FIXED("vcbus",	R8A779A0_CLK_VCBUS,	CLK_PLL5_DIV4,	1, 1),
-	DEF_FIXED("cbfusa",	R8A779A0_CLK_CBFUSA,	CLK_MAIN,	2, 1),
+	DEF_FIXED("cbfusa",	R8A779A0_CLK_CBFUSA,	CLK_EXTAL,	2, 1),
 
 	DEF_DIV6P1("mso",	R8A779A0_CLK_MSO,	CLK_PLL5_DIV4,	0x87c),
 	DEF_DIV6P1("canfd",	R8A779A0_CLK_CANFD,	CLK_PLL5_DIV4,	0x878),