evas-fb: Fix compiler warnings about suggested parentheses

Summary: Gcc suggested parens around the truth value here, however
as some developers don't like overly used parens, just modify the code
slightly to not use an if on the assignment line.

@fix

Signed-off-by: Chris Michael <cp.michael@samsung.com>

src/modules/evas/engines/fb/evas_engine.c

@@ -114,7 +114,8 @@ eng_output_free(void *data)
 {
    Render_Engine *re;
 
-   if (re = (Render_Engine *)data)
+   re = (Render_Engine *)data;
+   if (re)
      {
         evas_render_engine_software_generic_clean(&re->generic);
         free(re);