[ARM] Fix EBSA285 CLOCK_TICK_RATE.

The timex/time code requires CLOCK_TICK_RATE to be constant.  We
assume that the platform picks an appropriate clock source such
that we generate an exact HZ value, and set CLOCK_TICK_RATE to
a value where ACTHZ == HZ.

include/asm-arm/arch-ebsa285/time.h

@@ -181,12 +181,13 @@ set_isa_cmos_time(void)
 }
 
 
+static unsigned long timer1_latch;
 
 static unsigned long timer1_gettimeoffset (void)
 {
-	unsigned long value = LATCH - *CSR_TIMER1_VALUE;
+	unsigned long value = timer1_latch - *CSR_TIMER1_VALUE;
 
-	return ((tick_nsec / 1000) * value) / LATCH;
+	return ((tick_nsec / 1000) * value) / timer1_latch;
 }
 
 static irqreturn_t
@@ -260,8 +261,10 @@ void __init time_init(void)
 	    machine_is_personal_server()) {
 		gettimeoffset = timer1_gettimeoffset;
 
+		timer1_latch = (mem_fclk_21285 + 8 * HZ) / (16 * HZ);
+
 		*CSR_TIMER1_CLR  = 0;
-		*CSR_TIMER1_LOAD = LATCH;
+		*CSR_TIMER1_LOAD = timer1_latch;
 		*CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD | TIMER_CNTL_DIV16;
 
 		timer_irq.handler = timer1_interrupt;

include/asm-arm/arch-ebsa285/timex.h

@@ -11,8 +11,8 @@
  */
 
 /*
- * On EBSA285 boards, the clock runs at 50MHz and is
- * divided by a 4-bit prescaler.  Other boards use an
- * ISA derived timer, and this is unused.
+ * We assume a constant here; this satisfies the maths in linux/timex.h
+ * and linux/time.h.  CLOCK_TICK_RATE is actually system dependent, but
+ * this must be a constant.
  */
-#define CLOCK_TICK_RATE		(mem_fclk_21285 / 16)
+#define CLOCK_TICK_RATE		(50000000/16)