codechecker: Add assert for implicit condition

Since memReq is initialized inside the loop, codechecker
complained that we might use uninitialized data if count == 0.
So we assert that this is not the case to get rid of the
warning.

Change-Id: I82152942d2bb61723e9e41489c87bfde9f8bec15
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

src/gui/vulkan/qvulkanwindow.cpp

@@ -1330,6 +1330,7 @@ bool QVulkanWindowPrivate::createTransientImage(VkFormat format,
     VkMemoryRequirements memReq;
     VkResult err;
 
+    Q_ASSERT(count > 0);
     for (int i = 0; i < count; ++i) {
         VkImageCreateInfo imgInfo;
         memset(&imgInfo, 0, sizeof(imgInfo));