includecheck fix: include/linux, ftrace.h

fix the following 'make includecheck' warning:

  include/linux/ftrace.h: linux/sched.h is included more than once.
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Sam Ravnborg <sam@ravnborg.org>
LKML-Reference: <1247068321.4382.102.camel@ht.satnam>

include/linux/ftrace.h

@@ -446,7 +446,6 @@ static inline void unpause_graph_tracing(void) { }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 #ifdef CONFIG_TRACING
-#include <linux/sched.h>
 
 /* flags for current->trace */
 enum {