arm: Move timer_rate_hz into arch_global_data

Move this field into arch_global_data and tidy up.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/cpu/arm920t/a320/timer.c b/arch/arm/cpu/arm920t/a320/timer.c
index 4bfcef2..28736439 100644
--- a/arch/arm/cpu/arm920t/a320/timer.c
+++ b/arch/arm/cpu/arm920t/a320/timer.c
@@ -31,14 +31,14 @@
 static inline unsigned long long tick_to_time(unsigned long long tick)
 {
 	tick *= CONFIG_SYS_HZ;
-	do_div(tick, gd->timer_rate_hz);
+	do_div(tick, gd->arch.timer_rate_hz);
 
 	return tick;
 }
 
 static inline unsigned long long usec_to_tick(unsigned long long usec)
 {
-	usec *= gd->timer_rate_hz;
+	usec *= gd->arch.timer_rate_hz;
 	do_div(usec, 1000000);
 
 	return usec;
@@ -74,7 +74,7 @@
 	cr |= FTTMR010_TM3_ENABLE;
 	writel(cr, &tmr->cr);
 
-	gd->timer_rate_hz = TIMER_CLOCK;
+	gd->arch.timer_rate_hz = TIMER_CLOCK;
 	gd->tbu = gd->tbl = 0;
 
 	return 0;
@@ -126,5 +126,5 @@
  */
 ulong get_tbclk(void)
 {
-	return gd->timer_rate_hz;
+	return gd->arch.timer_rate_hz;
 }
diff --git a/arch/arm/cpu/arm920t/s3c24x0/timer.c b/arch/arm/cpu/arm920t/s3c24x0/timer.c
index d8668be..7694fea 100644
--- a/arch/arm/cpu/arm920t/s3c24x0/timer.c
+++ b/arch/arm/cpu/arm920t/s3c24x0/timer.c
@@ -52,7 +52,7 @@
 		 * @33.25MHz and 15625 @ 50 MHz
 		 */
 		gd->tbu = get_PCLK() / (2 * 16 * 100);
-		gd->timer_rate_hz = get_PCLK() / (2 * 16);
+		gd->arch.timer_rate_hz = get_PCLK() / (2 * 16);
 	}
 	/* load value for 10 ms timeout */
 	writel(gd->tbu, &timers->tcntb4);
@@ -93,7 +93,7 @@
 {
 	ulong tmr = get_ticks();
 
-	return tmr / (gd->timer_rate_hz / CONFIG_SYS_HZ);
+	return tmr / (gd->arch.timer_rate_hz / CONFIG_SYS_HZ);
 }
 
 void udelay_masked(unsigned long usec)