Make gm refinement step go all the way down to 1

-0.242% gain on cam_lowres

Change-Id: Ib9ba2f7dfc7d10b8066bd3f70eeafa7faac8a607
diff --git a/av1/encoder/encodeframe.c b/av1/encoder/encodeframe.c
index 5ff3724..070cea2 100644
--- a/av1/encoder/encodeframe.c
+++ b/av1/encoder/encodeframe.c
@@ -4834,7 +4834,7 @@
                   ref_buf[frame]->y_buffer, ref_buf[frame]->y_width,
                   ref_buf[frame]->y_height, ref_buf[frame]->y_stride,
                   cpi->source->y_buffer, cpi->source->y_width,
-                  cpi->source->y_height, cpi->source->y_stride, 3,
+                  cpi->source->y_height, cpi->source->y_stride, 5,
                   best_warp_error);
               if (warp_error < best_warp_error) {
                 best_warp_error = warp_error;
diff --git a/av1/encoder/global_motion.c b/av1/encoder/global_motion.c
index da1e403..116b815 100644
--- a/av1/encoder/global_motion.c
+++ b/av1/encoder/global_motion.c
@@ -156,7 +156,7 @@
                               d_width - 2 * border, d_height - 2 * border,
                               d_stride, 0, 0, 16, 16, best_frame_error);
   best_error = AOMMIN(best_error, best_frame_error);
-  step = 1 << (n_refinements + 1);
+  step = 1 << (n_refinements - 1);
   for (i = 0; i < n_refinements; i++, step >>= 1) {
     for (p = 0; p < n_params; ++p) {
       int step_dir = 0;