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/pc300too.c b/drivers/net/wan/pc300too.c
index 2226711..811e3af 100644
--- a/drivers/net/wan/pc300too.c
+++ b/drivers/net/wan/pc300too.c
@@ -128,7 +128,7 @@
 #define get_port(card, port)	     ((port) < (card)->n_ports ? \
 					 (&(card)->ports[port]) : (NULL))
 
-#include "hd6457x.c"
+#include "hd64572.c"
 
 
 static void pc300_set_iface(port_t *port)