demos: Fix uninitialized variables in vulkaninfo
demos: Fix uninitialized variables in vulkaninfo

Getting validation errors from uninitialized flags fields

Change-Id: I052cafcd3dc2cfd031b9d0ec75e654e318e1f320

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools