intel/ir: Pass block cycle count information explicitly to disassembler.

intel/ir: Pass block cycle count information explicitly to disassembler.

So we can eventually remove the cycle count estimates from the CFG
data structure and consolidate performance information in the
brw::performance object.

It would be cleaner to pass the brw::performance object directly to
the disassembler but that isn't straightforward since the disassembler
is built as a plain C file unlike the rest of the compiler back-end.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>