Fix warnings reported by doxygen

ctx.h

@@ -60,7 +60,7 @@ class FunctionEmitContext {
 public:
     /** Create a new FunctionEmitContext.
         @param function     The Function object representing the function
-        @param sym          Symbol that corresponds to the function
+        @param funSym       Symbol that corresponds to the function
         @param llvmFunction LLVM function in the current module that corresponds
                             to the function
         @param firstStmtPos Source file position of the first statement in the

opt.cpp

@@ -1647,6 +1647,9 @@ static void lPrintVector(const char *info, llvm::Value *elements[ISPC_MAX_NVEC])
     @param vectorLength      Number of elements in the given vector. (The
                              passed scalarizedVector array must also be at least
                              this length as well.)
+    @param phiMap            STL map from pointers to PHINodes that we've already
+                             scalarized to the array of Value *s that they were
+                             scalarized into.
     @returns                 True if the vector was successfully scalarized and
     the values in offsets[] are valid; false otherwise
 */