ACPICA: Support for custom ACPICA build for ACPI 5 reduced hardware

Add ACPI_REDUCED_HARDWARE flag that removes all hardware-related
code (about 10% code, 5% static data).

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpica/hwtimer.c b/drivers/acpi/acpica/hwtimer.c
index d4973d9..f1b2c3b 100644
--- a/drivers/acpi/acpica/hwtimer.c
+++ b/drivers/acpi/acpica/hwtimer.c
@@ -49,6 +49,7 @@
 #define _COMPONENT          ACPI_HARDWARE
 ACPI_MODULE_NAME("hwtimer")
 
+#if (!ACPI_REDUCED_HARDWARE)	/* Entire module */
 /******************************************************************************
  *
  * FUNCTION:    acpi_get_timer_resolution
@@ -187,3 +188,4 @@
 }
 
 ACPI_EXPORT_SYMBOL(acpi_get_timer_duration)
+#endif				/* !ACPI_REDUCED_HARDWARE */