i965/msaa: Switch on 8x MSAA for Gen7.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

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

@@ -154,8 +154,10 @@ brwCreateContext(int api,
    ctx->Const.MaxTransformFeedbackSeparateComponents =
       BRW_MAX_SOL_BINDINGS / BRW_MAX_SOL_BUFFERS;
 
-   if (intel->gen >= 6)
+   if (intel->gen == 6)
       ctx->Const.MaxSamples = 4;
+   else if (intel->gen >= 7)
+      ctx->Const.MaxSamples = 8;
 
    /* if conformance mode is set, swrast can handle any size AA point */
    ctx->Const.MaxPointSizeAA = 255.0;

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

@@ -193,8 +193,10 @@ quantize_num_samples(struct intel_context *intel, unsigned num_samples)
       else
          return 0;
    case 7:
-      /* TODO: Gen7 supports only 4x multisampling at the moment. */
-      if (num_samples > 0)
+      /* Gen7 supports 4x and 8x multisampling. */
+      if (num_samples > 4)
+         return 8;
+      else if (num_samples > 0)
          return 4;
       else
          return 0;