board: lsxl: remove unused header files

Cleanup the included header files in the board code. These are all
leftovers from earlier days.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/board/buffalo/lsxl/lsxl.c b/board/buffalo/lsxl/lsxl.c
index 106d46d..42221ee 100644
--- a/board/buffalo/lsxl/lsxl.c
+++ b/board/buffalo/lsxl/lsxl.c
@@ -11,12 +11,7 @@
 #include <bootstage.h>
 #include <command.h>
 #include <env.h>
-#include <env_internal.h>
 #include <init.h>
-#include <net.h>
-#include <malloc.h>
-#include <netdev.h>
-#include <miiphy.h>
 #include <spi.h>
 #include <spi_flash.h>
 #include <asm/arch/soc.h>