Add checks to see if selected board uses I2S

Author: JosipKuci

src/system/esp32/Esp.cpp

@@ -15,7 +15,7 @@
  *
  * @authors     Soldered
  ***************************************************/
-
+#ifdef USES_I2S
 #include "Esp.h"
 #include "../../boardSelect.h"
 
@@ -225,4 +225,5 @@ void IRAM_ATTR setI2S1pin(uint32_t _pin, uint32_t _function, uint32_t _inv)
     // Set the highest drive strength.
     ESP_REG(io_mux[_pin]) = 0;
     ESP_REG(io_mux[_pin]) = ((3 << FUN_DRV_S) | (2 << MCU_SEL_S));
-}
+}
+#endif