Add sa1100 get_ticks

diff -u -r1.2 interrupts.c
@@ -218,3 +218,24 @@
 	while (tmo >= get_timer_masked ())
 		/*NOP*/;
 }
+
+/*
+ * This function is derived from PowerPC code (read timebase as long long).
+ * On ARM it just returns the timer value.
+ */
+unsigned long long get_ticks(void)
+{
+	return get_timer(0);
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+ulong get_tbclk (void)
+{
+	ulong tbclk;
+
+	tbclk = CFG_HZ;
+	return tbclk;
+}