i965/vec4: Make type_size() return 0 for samplers.

i965/vec4: Make type_size() return 0 for samplers.

The FS backend has always used 0, and the VS backend has always used 1.
I think 1 is just working around other problems, and is incorrect.
Samplers are baked in; nothing uses the UNIFORM register we would
create, and we shouldn't upload any constant values for them.

Fixes ES3-CTS.shaders.struct.uniform.sampler_array_vertex.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Tested-by: Ian Romanick <ian.d.romanick@intel.com>