core: declare initVariant() as weak

Signed-off-by: Aymane Bahssain <[email protected]>

Author: Aymane-ST

Common.h

@@ -101,7 +101,7 @@ typedef uint8_t   byte;
 typedef uint16_t  word;
 
 void init(void);
-void initVariant(void);
+void initVariant() __attribute__((weak));
 
 #ifndef HOST
 int atexit(void (*func)()) __attribute__((weak));