time: x86: Remove CLOCK_TICK_RATE from acpi_pm clocksource driver

The acpi_pm clocksource driver uses CLOCK_TICK_RATE which is
defined as PIT_TICK_RATE on x86. This patch cleans it up to
just use the later so that CLOCK_TICK_RATE can be depecrated.

Signed-off-by: Deepak Saxena <dsaxena@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c
index effe797..6b5cf02 100644
--- a/drivers/clocksource/acpi_pm.c
+++ b/drivers/clocksource/acpi_pm.c
@@ -143,7 +143,7 @@
 #ifndef CONFIG_X86_64
 #include <asm/mach_timer.h>
 #define PMTMR_EXPECTED_RATE \
-  ((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (CLOCK_TICK_RATE>>10))
+  ((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (PIT_TICK_RATE>>10))
 /*
  * Some boards have the PMTMR running way too fast. We check
  * the PMTMR rate against PIT channel 2 to catch these cases.