RawModule with no reset should be able to use withClock method. (#1065)

* RawModule with no reset should be able to use withClock method.
- refactor ClockAndReset
  - now has `clockOpt: Option[Clock]` and `resetOpt: Option[Reset]` constructor params
  - convenience methods clock and reset tries to deref the option
  - ClockAndReset.empty is factory method for (None, None)
- In Builder
  - forcedClock does not check resetOpt now
  - forcedReset does not check clockOpt now
- withClock no longer looks at resetOpt
- withReset no longer looks at clockOpt
- Module starts with empty ClockAndReset

* RawModule with no reset should be able to use withClock method.
Refactor again based on @ducky64 comments
- refactor away ClockAndReset, now builder just has a
  - currentClock
  - currentReset
- withClock, withRest, withClockAndReset just use these fields directly

* RawModule with no reset should be able to use withClock method.
- Fixed typo in withReset handler, now picks up new reset

1 files changed, 2 insertions, 1 deletions

diff --git a/chiselFrontend/src/main/scala/chisel3/core/RawModule.scala b/chiselFrontend/src/main/scala/chisel3/core/RawModule.scala
index 397debcb..b224d9a3 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/RawModule.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/RawModule.scala
@@ -146,7 +146,8 @@ abstract class MultiIOModule(implicit moduleCompileOptions: CompileOptions)
   val reset: Reset = IO(Input(Bool()))
 
   // Setup ClockAndReset
-  Builder.currentClockAndReset = Some(ClockAndReset(clock, reset))
+  Builder.currentClock = Some(clock)
+  Builder.currentReset = Some(reset)
 
   private[core] override def initializeInParent(parentCompileOptions: CompileOptions): Unit = {
     implicit val sourceInfo = UnlocatableSourceInfo