Differentiate maxColorSamples and maxStencilSamples in GrCaps

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1592803002

Review URL: https://codereview.chromium.org/1592803002
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index e920144..79bbb5c 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -572,8 +572,7 @@
             chosenSampleCount = 16;
         }
     }
-    return chosenSampleCount <= fGpu->caps()->maxSampleCount() ?
-        chosenSampleCount : 0;
+    return chosenSampleCount <= fGpu->caps()->maxSampleCount() ? chosenSampleCount : 0;
 }