Changed multi-line C comments into another style.

The left side doesn't look unbalanced.

src/ld65/cfgexpr.c

@@ -230,8 +230,8 @@ long CfgConstExpr (void)
 
 long CfgCheckedConstExpr (long Min, long Max)
 /* Read an expression, make sure it's an int and in range, then return its
- * value.
- */
+** value.
+*/
 {
     /* Get the value */
     long Val = CfgConstExpr ();