anv,vulkan: Move drm_format_mod to vk_image

anv,vulkan: Move drm_format_mod to vk_image

Even though we can't really do the parsing on behalf of the driver (it's
too complicated), storing it in the vk_image lets us provide a common
implementation of vkGetImageDrmFormatModifierPropertiesEXT().  It'll
also be useful in the next few commits for swapchain images.

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12023>