Evas GL common: Force smooth scaling on miniature images

When evas GL uploads textures, it will first upload a 16x16 miniature
image, and then wait for some idle time in the main loop to upload the
high-res image.

Some images may not have smooth scaling enabled which results in the
miniature scaled with GL_NEAREST, showing big ugly squares. Let's
force smooth scaling instead, for a blur image rather than a
checkerboard.

src/modules/evas/engines/gl_common/evas_gl_context.c

@@ -1983,6 +1983,7 @@ evas_gl_common_context_image_push(Evas_Engine_GL_Context *gc,
         pt = tex->ptt;
         offsetx = tex->tx;
         offsety = tex->ty;
+        smooth = EINA_TRUE;
 
         // Adjusting sx, sy, sw and sh to real size of tiny texture
         sx = sx * (EVAS_GL_TILE_SIZE - 2) / tex->w;