ARM: mach-imx: Remove board entries in dt_board_compat

There is no need for adding board related entries into dt_board_compat.

Leave only the SoC entry.

This way we do not need to patch a C file when adding dt support for
a new board.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/mach-imx/imx51-dt.c

@@ -79,7 +79,6 @@ static struct sys_timer imx51_timer = {
 };
 
 static const char *imx51_dt_board_compat[] __initdata = {
-	"fsl,imx51-babbage",
 	"fsl,imx51",
 	NULL
 };