evas sw map render - make more optimal (but compiler already did it)

as pointed out by y.usishchev@samsung.com - this code is copy & paste
badness, but the compiler optimizer fixed it up already, so it made no
difference in real life.

src/lib/evas/common/evas_map_image_loop.c

@@ -90,7 +90,7 @@
         cv += cd; // col
 #   endif
 #   else                            
-        *d   = INTERP_256(rv, val3, val1);
+        *d   = val1;
 #   endif
 #  endif
         u += ud;