board_f: skip timer_init() on Coldfire archs

Coldfire arch is not happy with timer_init since interrupt handlers
are still not set at that stage, and the boot hangs silently.

Signed-off-by: Angelo Dureghello <angelo@sysam.it>
diff --git a/common/board_f.c b/common/board_f.c
index d9431ee..30e588e 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -740,7 +740,9 @@
 	/* get CPU and bus clocks according to the environment variable */
 	get_clocks,		/* get CPU and bus clocks (etc.) */
 #endif
+#if !defined(CONFIG_M68K)
 	timer_init,		/* initialize timer */
+#endif
 #if defined(CONFIG_BOARD_POSTCLK_INIT)
 	board_postclk_init,
 #endif