kcmkwin/compositing: Remove Crisp scale method

The OpenGL backend now supports only smooth and accurate scale methods.

src/kcmkwin/kwincompositing/compositing.ui

@@ -160,11 +160,6 @@ you can reset this protection but be aware that this might result in an immediat
     <layout class="QHBoxLayout" name="horizontalLayout">
      <item>
       <widget class="QComboBox" name="kcfg_glTextureFilter">
-       <item>
-        <property name="text">
-         <string>Crisp</string>
-        </property>
-       </item>
        <item>
         <property name="text">
          <string>Smooth</string>

src/kcmkwin/kwincompositing/kwincompositing_setting.kcfg

@@ -22,8 +22,12 @@
            </choices>
        </entry>
 
-       <entry name="glTextureFilter" key="GLTextureFilter" type="Int">
-           <default>2</default>
+       <entry name="glTextureFilter" key="GLTextureFilter" type="Enum">
+           <default>Accurate</default>
+           <choices>
+               <choice name="Smooth" value="1"/>
+               <choice name="Accurate" value="2"/>
+           </choices>
        </entry>
 
        <entry name="Enabled" type="Bool">

src/options.h

@@ -564,7 +564,7 @@ public:
         return m_hiddenPreviews;
     }
     // OpenGL
-    // 0 = no, 1 = yes when transformed,
+    // 1 = yes,
     // 2 = try trilinear when transformed; else 1,
     // -1 = auto
     int glSmoothScale() const {