If a function needs a frame pointer, but r11 (aka fp) has not been used,
remove it from the list of unspilled registers. Otherwise the following
attempt to keep the stack aligned by picking an extra GPR register to
spill will not work as it picks up r11.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208129 91177308-0d34-0410-b5e6-96231b3b80d8