[NFC] Fix comment of class InstrStage

[chenwj]

Summary

Class InstrStage has no member named NextCycles, should be TimeInc instead.

[chenwj]

@kparzysz Could you commit this for me? Thanks!

[chenwj]

@kparzysz ping?

include/llvm/Target/TargetItinerary.td

 def Required : ReservationKind<0>;
 def Reserved : ReservationKind<1>;
 
 //===----------------------------------------------------------------------===//
 // Instruction stage - These values represent a non-pipelined step in
 // the execution of an instruction.  Cycles represents the number of
 // discrete time slots needed to complete the stage.  Units represent
 // the choice of functional units that can be used to complete the
-// stage.  Eg. IntUnit1, IntUnit2. NextCycles indicates how many
-// cycles should elapse from the start of this stage to the start of
-// the next stage in the itinerary.  For example:
+// stage.  Eg. IntUnit1, IntUnit2. TimeInc indicates how many cycles
+// should elapse from the start of this stage to the start of the next
+// stage in the itinerary.  For example:
 //
 // A stage is specified in one of two ways:
 //
 //   InstrStage<1, [FU_x, FU_y]>     - TimeInc defaults to Cycles
 //   InstrStage<1, [FU_x, FU_y], 0>  - TimeInc explicit
 //
 
 class InstrStage<int cycles, list<FuncUnit> units,