i965: Move assign_common_binding_table_offsets to brw_program

i965: Move assign_common_binding_table_offsets to brw_program

This isn't used by Vulkan and is specific to the way the GL driver
works.  There's no reason to have it in common compiler code.  Also, it
relies on BRW_MAX_* defines which are defined in brw_context.h

Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>