The PIC and PIE levels are not independent. In fact, if PIE is defined
it is always the same as PIC.
This is clear in the driver where ParsePICArgs returns a PIC level and
a IsPIE boolean. Unfortunately that is currently lost and we pass two
redundant levels down the pipeline.
This patch keeps a bool and a PIC level all the way down to codegen.
llvm-svn: 273566