fix copy from ram to dataflash

If I try to "cp.b <ram> <dataflash>", u-boot selects normal flash
routines instead of dataflash. This is because it checks "if source
address is not dataflash" instead of target address.
Signed-off-by: NKim B. Heino <Kim.Heino@bluegiga.com>

common/cmd_mem.c

@@ -417,7 +417,7 @@ int do_mem_cp ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 	/* check if we are copying to Flash */
 	if ( (addr2info(dest) != NULL)
 #ifdef CONFIG_HAS_DATAFLASH
-	   && (!addr_dataflash(addr))
+	   && (!addr_dataflash(dest))
 #endif
 	   ) {
 		int rc;