glsl: Propagate UBO binding qualifier into UBO member variables.

glsl: Propagate UBO binding qualifier into UBO member variables.

Without an instance name, there is no ir_variable representing the
actual uniform block declaration.  When the linker goes to set uniform
initializers, it only sees the members as ir_variables; never the block.

So, unfortunately, the members need to know about the binding.

There has to be a better way to do this.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Paul Berry <stereotype441@gmail.com>