Fixes set pins return value in 2.0.13

[SuGlider]

Description of Change

Fixes a lack of return value in the uartSetPins() function. It doesn't prevent to build the firmware, but prints a warning message. With this fix, the warning message won't be displayed anymore.

This issue doesn't affect the uartSetPins() function because it only happens in the case that the HAL level is used with a UART number higher than the limit, which is very improbable.

    if(uart_num >= SOC_UART_NUM) {
        log_e("Serial number is invalid, please use numers from 0 to %u", SOC_UART_NUM - 1);
        return false;
    }

Tests scenarios

Just compiling and checking that the warning message is gone.

Related links

Closes #8641

[mrengineer7777]

LGTM. No other missing return statements in this file.