parisc: Fix ptrace check on syscall return

The TIF_XXX flags are stored in the flags field in the thread_info
struct (TI_FLAGS), not in the flags field of the task_struct structure
(TASK_FLAGS).

It seems this bug didn't generate any important side-effects, otherwise it
wouldn't have went unnoticed for 12 years (since v2.6.32).
Signed-off-by: Helge Deller <deller@gmx.de>
Fixes: ecd3d4bc ("parisc: stop using task->ptrace for {single,block}step flags")
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: stable@vger.kernel.org

arch/parisc/kernel/entry.S

@@ -1834,7 +1834,7 @@ syscall_restore:
 	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1
 
 	/* Are we being ptraced? */
-	ldw	TASK_FLAGS(%r1),%r19
+	LDREG	TI_FLAGS-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r19
 	ldi	_TIF_SYSCALL_TRACE_MASK,%r2
 	and,COND(=)	%r19,%r2,%r0
 	b,n	syscall_restore_rfi