Fix a typo in viewport validation test

BUG=dawn:53

Change-Id: I793373fa6e1fb167d5a8fe0a064c57ddf2ceedba
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/11281
Commit-Queue: Yunchao He <yunchao.he@intel.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

src/tests/unittests/validation/DynamicStateCommandValidationTests.cpp

@@ -202,7 +202,7 @@ TEST_F(SetViewportTest, MaxDepthOutOfRange) {
     }
 }
 
-// Test to check that minDepth equal or less than maxDepth is allowed
+// Test to check that minDepth equal or greater than maxDepth is allowed
 TEST_F(SetViewportTest, MinDepthEqualOrLessThanMaxDepth) {
     DummyRenderPass renderPass(device);