sh64: fix tracing of signals.

This follows the parisc change to ensure that tracehook_signal_handler()
is aware of when we are single-stepping in order to ptrace_notify()
appropriately. While this was implemented for 32-bit SH, sh64 neglected
to make use of TIF_SINGLESTEP when it was folded in with the 32-bit code,
resulting in ptrace_notify() never being called.

As sh64 uses all of the other abstractions already, this simply plugs in
the thread flag in the appropriate enable/disable paths and fixes up the
tracehook notification accordingly. With this in place, sh64 is brought
in line with what 32-bit is already doing.

Reported-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/signal_64.c b/arch/sh/kernel/signal_64.c
index ce76dbd..580e97d 100644
--- a/arch/sh/kernel/signal_64.c
+++ b/arch/sh/kernel/signal_64.c
@@ -118,7 +118,9 @@
 			 * clear the TS_RESTORE_SIGMASK flag.
 			 */
 			current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
-			tracehook_signal_handler(signr, &info, &ka, regs, 0);
+
+			tracehook_signal_handler(signr, &info, &ka, regs,
+					test_thread_flag(TIF_SINGLESTEP));
 			return 1;
 		}
 	}