Cleanup useless hooks

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

Author: fpistm

cores/arduino/hooks.c

@@ -30,32 +30,3 @@ static void __empty()
   // Empty
 }
 void yield(void) __attribute__((weak, alias("__empty")));
-
-/**
- * SysTick hook
- *
- * This function is called from SysTick handler, before the default
- * handler provided by Arduino.
- */
-static int __false()
-{
-  // Return false
-  return 0;
-}
-int sysTickHook(void) __attribute__((weak, alias("__false")));
-
-/**
- * SVC hook
- * PendSV hook
- *
- * These functions are called from SVC handler, and PensSV handler.
- * Default action is halting.
- */
-static void __halt()
-{
-  // Halts
-  while (1)
-    ;
-}
-void svcHook(void)    __attribute__((weak, alias("__halt")));
-void pendSVHook(void) __attribute__((weak, alias("__halt")));