Remove cpu_idcache_wbinv_all() from kdb_cpu_trap(), it's no longer needed.

This was added ca. 2004 for the purpose of ensuring the caches were in the
right state after the debugger set a breakpoint.  kdb_cpu_sync_icache()
was added in 2007 to handle that situation, and now the wbinv_all is
actually harmful because the operation isn't broadcast to other cores.

sys/arm/include/kdb.h

@@ -55,8 +55,6 @@ kdb_cpu_sync_icache(unsigned char *addr, size_t size)
 static __inline void
 kdb_cpu_trap(int type, int code)
 {
-
-	cpu_idcache_wbinv_all();
 }
 
 #endif /* _MACHINE_KDB_H_ */