[llvm] Hexagon: Move RuntimeLibcall setting out of TargetLowering (PR #142543)

[Matt Arsenault via llvm-commits]

================
@@ -7,10 +7,15 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/IR/RuntimeLibcalls.h"
+#include "llvm/Support/CommandLine.h"
 
 using namespace llvm;
 using namespace RTLIB;
 
+static cl::opt<bool>
+    HexagonEnableFastMathRuntimeCalls("hexagon-fast-math", cl::Hidden,
+                                      cl::desc("Enable Fast Math processing"));
----------------
arsenm wrote:

It's not even tested nor documented so probably not worth it. Probably should just delete it altogether 

https://github.com/llvm/llvm-project/pull/142543