This commit adds the last remaining bits to support input attachments in
the Intel Vulkan driver.  For color and depth attachments, we allocate an
input attachment surface state during vkCmdBeginRenderPass like we do for
the render target surface states.  This is so that we can incorporate the
clear color and aux information as used in rendering.  For stencil, we just
treat it like a regular texture because we don't there is no aux.  Also,
only having to worry about at most one input attachment surface for each
attachment makes some of the vkCmdBeginRenderPass code simpler.

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>