Remove unnecessary uses of reinterpret_cast.

Discovered while looking at compiler warnings (b/26936282).

Test: WITH_TIDY=1 WITH_STATIC_ANALYZER=1 mma
Change-Id: I66f8f6026ed732a504504ade93ff196dc8b727ca
diff --git a/minui/resources.cpp b/minui/resources.cpp
index 34e7b8b..9ccbf4b 100644
--- a/minui/resources.cpp
+++ b/minui/resources.cpp
@@ -308,7 +308,7 @@
     }
     free(p_row);
 
-    *pSurface = reinterpret_cast<GRSurface**>(surface);
+    *pSurface = surface;
 
 exit:
     png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
@@ -436,7 +436,7 @@
                 memcpy(surface->data + i*w, row.data(), w);
             }
 
-            *pSurface = reinterpret_cast<GRSurface*>(surface);
+            *pSurface = surface;
             break;
         } else {
             int i;