lwmon5: enable hardware watchdog

Some boards (e.g. lwmon5) may use rather small watchdog intervals, so
causing it to reboot the board if U-Boot does a long busy-wait with
udelay(). Thus, for these boards we have to restart WD more
frequently.

This patch splits the busy-wait udelay() into smaller, predefined,
intervals, so that the watchdog timer may be resetted with the
configurable (CONFIG_WD_PERIOD) interval.

Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
diff --git a/include/configs/lwmon5.h b/include/configs/lwmon5.h
index d8a2267..97e8bf1 100644
--- a/include/configs/lwmon5.h
+++ b/include/configs/lwmon5.h
@@ -366,12 +366,11 @@
 #define CFG_PCI_SUBSYS_VENDORID 0x10e8	/* AMCC				*/
 #define CFG_PCI_SUBSYS_ID       0xcafe	/* Whatever			*/
 
-#if 0
 /*
  * ToDo: Watchdog is not test fully, so exclude it for now
  */
 #define CONFIG_HW_WATCHDOG	1	/* Use external HW-Watchdog	*/
-#endif
+#define CONFIG_WD_PERIOD	40000	/* in usec */
 
 /*
  * For booting Linux, the board info and command line data