ARM: i.MX25: Fix DT compilation

The i.MX25 DT machine descriptor calls a non existing imx25_timer_init()
function. This patch adds it to fix compilation.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/mach-imx/imx25-dt.c

@@ -27,6 +27,11 @@ static const char * const imx25_dt_board_compat[] __initconst = {
 	NULL
 };
 
+static void __init imx25_timer_init(void)
+{
+	mx25_clocks_init_dt();
+}
+
 DT_MACHINE_START(IMX25_DT, "Freescale i.MX25 (Device Tree Support)")
 	.map_io		= mx25_map_io,
 	.init_early	= imx25_init_early,