ilo: let ilo_shader_compile_cs() return a dummy shader

The dummy shader sends an EOT message to end itself.  There are many more
works need to be done on the compiler side before we can advertise
PIPE_CAP_COMPUTE.

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
ilo: OpenCL hello world hacks

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>