Fix PT2811 crash on Teensy 4.x

https://forum.pjrc.com/threads/64388-PT8211-and-Teensy-4?p=259415&viewfull=1#post259415

output_pt8211.cpp

@@ -237,7 +237,7 @@ void AudioOutputPT8211::isr(void)
 					oldL = val;
 				}
 			#elif defined(AUDIO_PT8211_INTERPOLATION_CIC)
-				for (int i=0; i< AUDIO_BLOCK_SAMPLES / 2; i++, offsetL++, offsetR++) {
+				for (int i=0; i< AUDIO_BLOCK_SAMPLES / 2; i++, offsetL++) {
 					int32_t valL = blockL->data[offsetL];
 
 					int32_t combL[3] = {0};
@@ -296,7 +296,7 @@ void AudioOutputPT8211::isr(void)
 					oldR = val;
 				}
 			#elif defined(AUDIO_PT8211_INTERPOLATION_CIC)
-				for (int i=0; i< AUDIO_BLOCK_SAMPLES / 2; i++, offsetL++, offsetR++) {
+				for (int i=0; i< AUDIO_BLOCK_SAMPLES / 2; i++, offsetR++) {
 					int32_t valR = blockR->data[offsetR];
 
 					int32_t combR[3] = {0};

output_pt8211_2.cpp

@@ -206,7 +206,7 @@ void AudioOutputPT8211_2::isr(void)
 					oldL = val;
 				}
 			#elif defined(AUDIO_PT8211_INTERPOLATION_CIC)
-				for (int i=0; i< AUDIO_BLOCK_SAMPLES / 2; i++, offsetL++, offsetR++) {
+				for (int i=0; i< AUDIO_BLOCK_SAMPLES / 2; i++, offsetL++) {
 					int32_t valL = blockL->data[offsetL];
 
 					int32_t combL[3] = {0};
@@ -265,7 +265,7 @@ void AudioOutputPT8211_2::isr(void)
 					oldR = val;
 				}
 			#elif defined(AUDIO_PT8211_INTERPOLATION_CIC)
-				for (int i=0; i< AUDIO_BLOCK_SAMPLES / 2; i++, offsetL++, offsetR++) {
+				for (int i=0; i< AUDIO_BLOCK_SAMPLES / 2; i++, offsetR++) {
 					int32_t valR = blockR->data[offsetR];
 
 					int32_t combR[3] = {0};