via-velocity: allow MTU size less than 1500 bytes

Change the minimum allowable MTU size from 1500 bytes to 64 bytes.
Signed-off-by: NJay Cliburn <jacliburn@bellsouth.net>

drivers/net/via-velocity.h

@@ -307,7 +307,7 @@ enum  velocity_owner {
 #define TX_QUEUE_NO         4
 
 #define MAX_HW_MIB_COUNTER  32
-#define VELOCITY_MIN_MTU    (1514-14)
+#define VELOCITY_MIN_MTU    (64)
 #define VELOCITY_MAX_MTU    (9000)
 
 /*