[M68k] Fix compilation pipeline check

- Add 'Init Undef Pass', which is target-independent now.

Author: darkbuck

llvm/test/CodeGen/M68k/pipeline.ll

@@ -76,6 +76,7 @@
 ; CHECK-NEXT:      Peephole Optimizations
 ; CHECK-NEXT:      Remove dead machine instructions
 ; CHECK-NEXT:      Detect Dead Lanes
+; CHECK-NEXT:      Init Undef Pass
 ; CHECK-NEXT:      Process Implicit Definitions
 ; CHECK-NEXT:      Remove unreachable machine basic blocks
 ; CHECK-NEXT:      Live Variable Analysis