soc/rtc_clk: don’t clear DPORT_CPUPERIOD_SEL when switching to XTAL
soc/rtc_clk: don’t clear DPORT_CPUPERIOD_SEL when switching to XTAL

This is not necessary since RTC_CNTL_SOC_CLK_SEL is set before this.

espressif/esp-idf,espressif/esp-idf,espressif/esp-idf,espressif/esp-idf