Don't include STM32 Core code when compiling STM32 Generic (#12575)

Marlin/src/HAL/HAL_STM32/HAL.cpp

Marlin/src/HAL/HAL_STM32/HAL_Servo_STM32.cpp

Marlin/src/HAL/HAL_STM32/HAL_spi_STM32.cpp

Marlin/src/HAL/HAL_STM32/HAL_timers_STM32.cpp

Marlin/src/HAL/HAL_STM32/fastio_STM32.cpp

Marlin/src/HAL/HAL_STM32/persistent_store_impl.cpp

Marlin/src/HAL/HAL_STM32/watchdog_STM32.cpp

Marlin/src/HAL/HAL_STM32F4/EEPROM_Emul/eeprom_emul.cpp

Marlin/src/HAL/HAL_STM32F4/EmulatedEeprom.cpp

Marlin/src/HAL/HAL_STM32F4/HAL.cpp

Marlin/src/HAL/HAL_STM32F4/HAL_Servo_STM32F4.cpp

Marlin/src/HAL/HAL_STM32F4/HAL_spi_STM32F4.cpp

Marlin/src/HAL/HAL_STM32F4/HAL_timers_STM32F4.cpp

Marlin/src/HAL/HAL_STM32F4/persistent_store_eeprom.cpp

Marlin/src/HAL/HAL_STM32F4/watchdog_STM32F4.cpp