fix(uart): variable name, typo error

Author: SuGlider

cores/esp32/esp32-hal-uart.c

@@ -1022,7 +1022,7 @@ bool uartSetBaudRate(uart_t *uart, uint32_t baud_rate) {
       newClkSrc = UART_SCLK_XTAL;  // valid for C2, S3, C3, C6, H2 and P4
       log_v("Setting UART%d to use XTAL clock", uart->num);
 #elif SOC_UART_SUPPORT_REF_TICK
-      if (baudrate <= REF_TICK_BAUDRATE_LIMIT) {
+      if (baud_rate <= REF_TICK_BAUDRATE_LIMIT) {
         newClkSrc = UART_SCLK_REF_TICK;  // valid for ESP32, S2 - MAX supported baud rate is 250 Kbps
         log_v("Setting UART%d to use REF_TICK clock", uart->num);
       } else {