ESP32 AudioOutputULP fixes (#579)

* Fix ULP on ESP32

CONFIG_IDF_TARGET_ESP32 is not yet defined before #include "AudioOutputULP.h"

* AudioOutputULP: Fix DAC2 stereo in case of DAC1+DAC2

* ULP - no ESP32S2 / S3

On ESP32S2 it compiles, but no audio is coming out
On ESP32S3 DAC is not supported

* Astyle

---------

Co-authored-by: Earle F. Philhower, III <earlephilhower@yahoo.com>

Author: FedericoBusero

src/AudioOutputULP.cpp

@@ -18,9 +18,12 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2
+#ifdef ESP32
 
 #include "AudioOutputULP.h"
+
+#if CONFIG_IDF_TARGET_ESP32
+
 #include <esp32/ulp.h>
 #include <driver/rtc_io.h>
 #include <soc/rtc_io_reg.h>
@@ -174,7 +177,7 @@ bool AudioOutputULP::begin() {
         for (int i = 0; i < 256; i++) {
             RTC_SLOW_MEM[dacTableStart1 + i * 2] = create_I_WR_REG(RTC_IO_PAD_DAC1_REG, 19, 26, i); //dac1: 0x1D4C0121 | (i << 10)
             RTC_SLOW_MEM[dacTableStart1 + 1 + i * 2] = create_I_BXI(retAddress1); // 0x80000000 + retAddress1 * 4
-            RTC_SLOW_MEM[dacTableStart2 + i * 2] = create_I_WR_REG(RTC_IO_PAD_DAC1_REG, 19, 26, i); //dac2: 0x1D4C0122 | (i << 10)
+            RTC_SLOW_MEM[dacTableStart2 + i * 2] = create_I_WR_REG(RTC_IO_PAD_DAC2_REG, 19, 26, i); //dac2: 0x1D4C0122 | (i << 10)
             RTC_SLOW_MEM[dacTableStart2 + 1 + i * 2] = create_I_BXI(retAddress2); // 0x80000000 + retAddress2 * 4
         }
         break;
@@ -270,3 +273,4 @@ bool AudioOutputULP::stop() {
 }
 
 #endif
+#endif