mesa: associate uniform storage to bindless samplers/images

mesa: associate uniform storage to bindless samplers/images

When a bindless sampler/image is bound to a texture/image unit,
we have to overwrite the constant value by the resident handle
directly in the constant buffer before the next draw.

One solution is to keep track of a pointer to the data.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>