clk: ti: am33xx: fix RTC clock parent

Right now, trying to use RTC purely with the ti-sysc / clkctrl framework
fails to enable the RTC module properly. Based on experimentation, this
appears to be because RTC is sourced from the clkdiv32k optional clock.
TRM is not very clear on this topic, but fix the RTC to use the proper
source clock nevertheless.

Reported-by: Tony Lindgren <[e-mail]>
Signed-off-by: Tero Kristo <[e-mail]>
Link: https://lkml.kernel.org/r/[e-mail]
Acked-by: Tony Lindgren <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/ti/clk-33xx.c

···
 };
 
 static const struct omap_clkctrl_reg_data am3_l4_rtc_clkctrl_regs[] __initconst = {
-	{ AM3_L4_RTC_RTC_CLKCTRL, NULL, CLKF_SW_SUP, "clk_32768_ck" },
+	{ AM3_L4_RTC_RTC_CLKCTRL, NULL, CLKF_SW_SUP, "clk-24mhz-clkctrl:0000:0" },
 	{ 0 },
 };