vlib rename vlib_frame_args(...) to vlib_frame_scalar_args(..)

Typically we have scalar_size == 0, so it doesn't matter
but vlib_frame_args was providing pointer to scalar frame
data, not vector data. To avoid future confusion function
is renamed to vlib_frame_scalar_args(...)

Change-Id: I48b75523b46d487feea24f3f3cb10c528dde516f
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vnet/devices/pipe/pipe.c b/src/vnet/devices/pipe/pipe.c
index 8b30f47..f45c088 100644
--- a/src/vnet/devices/pipe/pipe.c
+++ b/src/vnet/devices/pipe/pipe.c
@@ -140,7 +140,7 @@
   pipe_t *pipe;
 
   n_left_from = frame->n_vectors;
-  from = vlib_frame_args (frame);
+  from = vlib_frame_vector_args (frame);
 
   while (n_left_from > 0)
     {