Bug surried over from mtc.

Author: SpenceKonde

megaavr/cores/dxcore/UART4.cpp

@@ -82,7 +82,7 @@
   #endif
   #if !(defined(USE_ASM_DRE) && USE_ASM_DRE == 1 && \
        (SERIAL_RX_BUFFER_SIZE == 256 || SERIAL_RX_BUFFER_SIZE == 128 || SERIAL_RX_BUFFER_SIZE == 64 || SERIAL_RX_BUFFER_SIZE == 32 || SERIAL_RX_BUFFER_SIZE == 16) && \
-       (SERIAL_RX_BUFFER_SIZE == 256 || SERIAL_TX_BUFFER_SIZE == 128 || SERIAL_TX_BUFFER_SIZE == 64 || SERIAL_TX_BUFFER_SIZE == 32 || SERIAL_TX_BUFFER_SIZE == 16))
+       (SERIAL_TX_BUFFER_SIZE == 256 || SERIAL_TX_BUFFER_SIZE == 128 || SERIAL_TX_BUFFER_SIZE == 64 || SERIAL_TX_BUFFER_SIZE == 32 || SERIAL_TX_BUFFER_SIZE == 16))
     ISR(USART4_DRE_vect) {
       HardwareSerial::_tx_data_empty_irq(Serial);
     }