While VkPipelineStageFlags is an enum (arguably backed as uint32 in 32bit
platforms), VkPipelineStageFlags2 is a redefinition of guint64; likewise for
VkAccessFlags and VkAccessFlags2.
This patch types both members in GstVulkanBarrierMemoryInfo as guint64 for
compatibility, so it could be used with or without synchronization2 vulkan
extension.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5079>