android: enable VK_ANDROID_native_buffer

android: enable VK_ANDROID_native_buffer

Patch changes entrypoints generator to not skip this extension even
though it is set as disabled in the xml. We also need compilation
flag VK_USE_PLATFORM_ANDROID_KHR to be enabled.

It looks like this extension got disabled in commit 69f447553c.

v2: just remove the whole 'supported' attrib check + remove
    vk_icd.h compilation fix (fix in VulkanHeaders instead)

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>