wined3d: Make minMipLookup_noFilter and magLookup_noFilter const.

Note that minMipLookup and magLookup aren't particularly safe to use,
they're global arrays initialized from IWineD3DImpl_FillGLCaps(). The same
goes for the other global dynamic lookup tables.
diff --git a/dlls/wined3d/wined3d_private.h b/dlls/wined3d/wined3d_private.h
index a202884..6ea6663 100644
--- a/dlls/wined3d/wined3d_private.h
+++ b/dlls/wined3d/wined3d_private.h
@@ -111,13 +111,18 @@
 extern int maxLookup[MAX_LOOKUPS];
 extern DWORD *stateLookup[MAX_LOOKUPS];
 
-typedef DWORD magLookup_t[WINED3DTEXF_ANISOTROPIC + 1];
-extern magLookup_t magLookup;
-extern magLookup_t magLookup_noFilter;
+struct min_lookup
+{
+    GLenum mip[WINED3DTEXF_LINEAR + 1];
+};
 
-typedef DWORD minMipLookup_t[WINED3DTEXF_ANISOTROPIC + 1][WINED3DTEXF_LINEAR + 1];
-extern minMipLookup_t minMipLookup;
-extern minMipLookup_t minMipLookup_noFilter;
+struct min_lookup minMipLookup[WINED3DTEXF_ANISOTROPIC + 1];
+const struct min_lookup minMipLookup_noFilter[WINED3DTEXF_ANISOTROPIC + 1];
+GLenum magLookup[WINED3DTEXF_ANISOTROPIC + 1];
+const GLenum magLookup_noFilter[WINED3DTEXF_ANISOTROPIC + 1];
+
+extern const struct filter_lookup filter_lookup_nofilter;
+extern struct filter_lookup filter_lookup;
 
 void init_type_lookup(WineD3D_GL_Info *gl_info);
 #define WINED3D_ATR_TYPE(type)          GLINFO_LOCATION.glTypeLookup[type].d3dType
@@ -1229,8 +1234,8 @@
     UINT                    srgb_mode_change_count;
     WINED3DFORMAT           shader_conversion_group;
     float                   pow2Matrix[16];
-    minMipLookup_t          *minMipLookup;
-    magLookup_t             *magLookup;
+    const struct min_lookup *minMipLookup;
+    const GLenum            *magLookup;
 } IWineD3DBaseTextureClass;
 
 typedef struct IWineD3DBaseTextureImpl