Add mssa configs for vulkan, and simple bug fix

src/gpu/vk/GrVkUtil.cpp

Index: src/gpu/vk/GrVkUtil.cpp
diff --git a/src/gpu/vk/GrVkUtil.cpp b/src/gpu/vk/GrVkUtil.cpp
index ffbad25fd9a29753a5b05dc7975a20a816cbc70c..e0d5daf99dc001437f993bc47414ddd92138c404 100644
--- a/src/gpu/vk/GrVkUtil.cpp
+++ b/src/gpu/vk/GrVkUtil.cpp
@@ -231,19 +231,19 @@ bool GrSampleCountToVkSampleCount(uint32_t samples, VkSampleCountFlagBits* vkSam
             *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;