powerpc: Don't use the wrong thread_struct for ptrace get/set VSX regs

In PTRACE_GET/SETVSRREGS, we should be using the thread we are
ptracing rather than current.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/ptrace.c

@@ -375,7 +375,7 @@ static int vsr_get(struct task_struct *target, const struct user_regset *regset,
 	flush_vsx_to_thread(target);
 
 	for (i = 0; i < 32 ; i++)
-		buf[i] = current->thread.fpr[i][TS_VSRLOWOFFSET];
+		buf[i] = target->thread.fpr[i][TS_VSRLOWOFFSET];
 	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 				  buf, 0, 32 * sizeof(double));
 
@@ -394,7 +394,7 @@ static int vsr_set(struct task_struct *target, const struct user_regset *regset,
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 				 buf, 0, 32 * sizeof(double));
 	for (i = 0; i < 32 ; i++)
-		current->thread.fpr[i][TS_VSRLOWOFFSET] = buf[i];
+		target->thread.fpr[i][TS_VSRLOWOFFSET] = buf[i];
 
 
 	return ret;