compositor-drm: Fix refresh rate selection in drm_output_switch_mode

The matching logic in choose_mode() compared refresh rate
of a drm_mode candidate mode expressed in Hz against the
requested refresh rate of the target weston_mode expressed
in milliHz, so the match always failed and the logic always
ended up the mode with the highest refresh rate for a given
resolution, instead of the one matching the requested rate.

Match proper fields to fix this.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>

src/compositor-drm.c

@@ -1225,7 +1225,7 @@ choose_mode (struct drm_output *output, struct weston_mode *target_mode)
 	wl_list_for_each(mode, &output->base.mode_list, base.link) {
 		if (mode->mode_info.hdisplay == target_mode->width &&
 		    mode->mode_info.vdisplay == target_mode->height) {
-			if (mode->mode_info.vrefresh == target_mode->refresh ||
+			if (mode->base.refresh == target_mode->refresh ||
 			    target_mode->refresh == 0) {
 				return mode;
 			} else if (!tmp_mode)