intel: fix max anisotropy supported

i915 actually supports up to 4 (according to header file - not tested),
i965 up to 16 (code already handled this but slightly broken), so don't use 2
for all chips, even though angular dependency is very high.

src/mesa/drivers/dri/i915/i830_context.c

@@ -98,6 +98,8 @@ i830CreateContext(const __GLcontextModes * mesaVis,
    ctx->Const.MaxTextureRectSize = (1 << 11);
    ctx->Const.MaxTextureUnits = I830_TEX_UNITS;
 
+   ctx->Const.MaxTextureMaxAnisotropy = 2.0;
+
    ctx->Const.MaxDrawBuffers = 1;
 
    _tnl_init_vertices(ctx, ctx->Const.MaxArrayLockSize + 12,

src/mesa/drivers/dri/i915/i915_context.c

@@ -145,6 +145,8 @@ i915CreateContext(const __GLcontextModes * mesaVis,
    ctx->Const.MaxTextureRectSize = (1 << 11);
    ctx->Const.MaxTextureUnits = I915_TEX_UNITS;
 
+   ctx->Const.MaxTextureMaxAnisotropy = 4.0;
+
    /* GL_ARB_fragment_program limits - don't think Mesa actually
     * validates programs against these, and in any case one ARB
     * instruction can translate to more than one HW instruction, so

src/mesa/drivers/dri/i965/brw_context.c

@@ -118,6 +118,8 @@ GLboolean brwCreateContext( const __GLcontextModes *mesaVis,
    ctx->Const.MaxCubeTextureLevels = 12;
    ctx->Const.MaxTextureRectSize = (1<<12);
    
+   ctx->Const.MaxTextureMaxAnisotropy = 16.0;
+
    /* if conformance mode is set, swrast can handle any size AA point */
    ctx->Const.MaxPointSizeAA = 255.0;
 

src/mesa/drivers/dri/i965/brw_wm_sampler_state.c

@@ -152,7 +152,7 @@ static void brw_update_sampler_state(struct wm_sampler_entry *key,
       sampler->ss0.mag_filter = BRW_MAPFILTER_ANISOTROPIC;
 
       if (key->max_aniso > 2.0) {
-	 sampler->ss3.max_aniso = MAX2((key->max_aniso - 2) / 2,
+	 sampler->ss3.max_aniso = MIN2((key->max_aniso - 2) / 2,
 				       BRW_ANISORATIO_16);
       }
    }

src/mesa/drivers/dri/intel/intel_context.c

@@ -528,8 +528,6 @@ intelInitContext(struct intel_context *intel,
       }
    }
 
-   ctx->Const.MaxTextureMaxAnisotropy = 2.0;
-
    /* This doesn't yet catch all non-conformant rendering, but it's a
     * start.
     */