fixes UART at lower than 80MHz | S3 C3

[SuGlider]

Description of Change

This PR fixes UART baud rate when ESP32-S3 and ESP32-C3 are running under 80MHz.

Tests scenarios

Using ESP32, ESP32-S2, ESP32-S3 and ESP32-C3

Testing sketch:

uint32_t Freq = 0;
const int bauds = 115200;
uint8_t cpufreqs[] = {240, 160, 80, 40, 20, 10};
int i = 0;

void setup() {
  Freq = getCpuFrequencyMhz();

  Serial.begin(bauds);
  delay(500);

  Freq = getCpuFrequencyMhz();
  Serial.print("CPU Freq = ");
  Serial.print(Freq);
  Serial.println(" MHz");
  Freq = getXtalFrequencyMhz();
  Serial.print("XTAL Freq = ");
  Serial.print(Freq);
  Serial.println(" MHz");
  Freq = getApbFrequency();
  Serial.print("APB Freq = ");
  Serial.print(Freq);
  Serial.println(" Hz");
}
void loop() {
  Serial.print("\nchange CPU freq to ");
  Serial.println(cpufreqs[i]);
  delay(1000);
  
  setCpuFrequencyMhz(cpufreqs[i]);

  Freq = getCpuFrequencyMhz();

  Serial.end();
  Serial.begin(bauds);

  Serial.print("Sending to serial with baud rate = ");
  Serial.println(bauds);
  Serial.print("CPU Freq = ");
  Serial.print(Freq);
  Serial.println(" MHz");

  delay(1000);
  i++;
  i = i % sizeof(cpufreqs);
}

Related links

Fix #7182

[P-R-O-C-H-Y]

Tested on all chips before/after changes. Fixes the UART baud rate for C3/S3.
Great fix @SuGlider, LGTM!

[aeonSolutions]

i confirm it is working for serial send , Serial.print() command

however it is not working for Serial.read()

I'm currently testing at 10MHz same ESP32 S3 with 8MB and no Serial.read()