arch/sparc64/kernel/signal.c: removed duplicated #include

Removed duplicated #include <linux/tracehook.h> in
arch/sparc64/kernel/signal.c.
Signed-off-by: NHuang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc64/kernel/signal.c

@@ -23,7 +23,6 @@
 #include <linux/tty.h>
 #include <linux/binfmts.h>
 #include <linux/bitops.h>
-#include <linux/tracehook.h>
 
 #include <asm/uaccess.h>
 #include <asm/ptrace.h>