[Hexagon] Fix an incorrect assertion in HexagonConstExtenders.cpp

Making sure that an instruction has fewer operands than required, then
attempting to access one out of range is going to fail.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316785 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed