evas: fix memory leak

Summary:
Fix of memory leak in evas_3d_utils.c

@fix

Reviewers: raster, Hermet, cedric

Reviewed By: cedric

Subscribers: artem.popov

Differential Revision: https://phab.enlightenment.org/D3196

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>

src/lib/evas/include/evas_3d_utils.h

@@ -2927,6 +2927,7 @@ evas_tangent_space_get(float *data, float *tex_data, float *normal_data, unsigne
 
    memcpy(*tangent, tmp_tangent, (3 * vertex_count) * sizeof(float));
    free(tmp_tangent);
+   free(plain);
 
    return;
 }