Removed unnecessary comparisons when lowercasing a string.

src/xspice/cmpp/util.c

@@ -85,9 +85,7 @@ void str_to_lower(char *s)
     char    c;
 
     for(i = 0; (c = s[i]) != '\0'; i++)
-        if(isalpha_c(c))
-            if(isupper_c(c))
-                s[i] = tolower_c(c);
+        s[i] = tolower_c(c);
 }