intel/fs: Add helper functions inferring sync and exec pipeline of an instruction.

intel/fs: Add helper functions inferring sync and exec pipeline of an instruction.

Define two helper functions local to the software scoreboard lowering
pass describing the behavior of the hardware and code generator:
inferred_sync_pipe() calculates the ALU pipeline the hardware will
implicitly synchronize with when a RegDist SWSB annotation is used
without providing explicit pipeline synchronization information,
inferred_exec_pipe() infers the ALU pipeline that will execute the
instruction.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10000>