🩹 Remove extraneous 'inline'

See #26085

Marlin/src/HAL/STM32F1/MarlinSerial.cpp

@@ -28,7 +28,7 @@
 
 // Copied from ~/.platformio/packages/framework-arduinoststm32-maple/STM32F1/system/libmaple/usart_private.h
 // Changed to handle Emergency Parser
-static inline __always_inline void my_usart_irq(ring_buffer *rb, ring_buffer *wb, usart_reg_map *regs, MSerialT &serial) {
+static __always_inline void my_usart_irq(ring_buffer *rb, ring_buffer *wb, usart_reg_map *regs, MSerialT &serial) {
  /* Handle RXNEIE and TXEIE interrupts.
   * RXNE signifies availability of a byte in DR.
   *