Remove useless variant.h include

variant.h is now included thanks stm32_def.h

See stm32duino/Arduino_Core_STM32#518

Signed-off-by: Frederic.Pillon <frederic.pillon@st.com>

Author: fpistm

src/utility/ethernetif.c

@@ -52,7 +52,9 @@
 #include <string.h>
 #include "PeripheralPins.h"
 #include "stm32_eth.h"
+#if !defined(STM32_CORE_VERSION) || (STM32_CORE_VERSION  <= 0x01050000)
 #include "variant.h"
+#endif
 
 #ifdef __cplusplus
  extern "C" {