WAN: split hd6457x.c into hd64570.c and hd64572.c

Supporting both original SCA and SCA-II in one file was nice at some
point but now it's increasingly painful.

Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
diff --git a/drivers/net/wan/c101.c b/drivers/net/wan/c101.c
index c8e5631..23d6606 100644
--- a/drivers/net/wan/c101.c
+++ b/drivers/net/wan/c101.c
@@ -113,7 +113,7 @@
 }
 
 
-#include "hd6457x.c"
+#include "hd64570.c"
 
 
 static inline void set_carrier(port_t *port)