Add mssa configs for vulkan, and simple bug fix

BUG=skia:5127
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2251473002

Review-Url: https://codereview.chromium.org/2251473002
diff --git a/src/gpu/vk/GrVkUtil.cpp b/src/gpu/vk/GrVkUtil.cpp
index ffbad25..e0d5daf 100644
--- a/src/gpu/vk/GrVkUtil.cpp
+++ b/src/gpu/vk/GrVkUtil.cpp
@@ -231,19 +231,19 @@
             *vkSamples = VK_SAMPLE_COUNT_2_BIT;
             return true;
         case 4:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_4_BIT;
             return true;
         case 8:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_8_BIT;
             return true;
         case 16:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_16_BIT;
             return true;
         case 32:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_32_BIT;
             return true;
         case 64:
-            *vkSamples = VK_SAMPLE_COUNT_2_BIT;
+            *vkSamples = VK_SAMPLE_COUNT_64_BIT;
             return true;
         default:
             return false;