gallium: make set_shader_resources work per stage rather than globally

This isn't used anywhere, so also disable the two existing
implementations of this function in ilo and nvc0.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
tgsi: add ureg support for resource decls

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
mesa/st: add atomic buffer support

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
nvc0: allow binding resources

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>