consolidate mdelay by providing a common function for all users

There are several mdelay() definitions in the driver and
board code. Remove them all and provide a common mdelay()
in lib/time.c.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>

lib/time.c

@@ -41,3 +41,9 @@ void udelay(unsigned long usec)
 		usec -= kv;
 	} while(usec);
 }
+
+void mdelay(unsigned long msec)
+{
+	while (msec--)
+		udelay(1000);
+}