android: add vulkan build for intel

android: add vulkan build for intel

fixes to issues spotted by Emil Velikov:

   - set ANV_TIMESTAMP corretly
   - fix typo with VULKAN_GEM_FILES

v2: update to use Makefile.sources under vulkan
    instead of having own

v3: update to changes to generate from vk.xml
    (commit c7fc310)

v4: remove 'hw' relative path
    cleanups, remove unnecessary cruft

    review from Emil Velikov:

    - move to vulkan folder
    - remove timestamp gen, no longer necessary
    - more cleanups

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>