Feed the watchdog in u-boot for 8610 board.

The watchdog on 8610 board is enabled by setting sw[6]
to on. Once enabled, the watchdog can not be disabled
by software. So feed the dog in u-boot is necessary for
normal operation.

Signed-off-by: Jason Jin <Jason.jin@freescale.com>
diff --git a/cpu/mpc86xx/interrupts.c b/cpu/mpc86xx/interrupts.c
index d9f634f..f16744b 100644
--- a/cpu/mpc86xx/interrupts.c
+++ b/cpu/mpc86xx/interrupts.c
@@ -36,6 +36,7 @@
 #include <command.h>
 #include <asm/processor.h>
 #include <ppc_asm.tmpl>
+#include <watchdog.h>
 
 unsigned long decrementer_count;    /* count value for 1e6/HZ microseconds */
 unsigned long timestamp;