On Hexagon is it legal to packetize the instructions setting up call
arguments with the call instruction itself. This was already done,
except for tail calls. Make sure tail calls are handled as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275458 91177308-0d34-0410-b5e6-96231b3b80d8
