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/hwregs.c b/drivers/acpi/acpica/hwregs.c
index 4ea4eeb5..17a78e5 100644
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -51,6 +51,7 @@
 #define _COMPONENT          ACPI_HARDWARE
 ACPI_MODULE_NAME("hwregs")
 
+#if (!ACPI_REDUCED_HARDWARE)
 /* Local Prototypes */
 static acpi_status
 acpi_hw_read_multiple(u32 *value,
@@ -62,6 +63,8 @@
 		       struct acpi_generic_address *register_a,
 		       struct acpi_generic_address *register_b);
 
+#endif				/* !ACPI_REDUCED_HARDWARE */
+
 /******************************************************************************
  *
  * FUNCTION:    acpi_hw_validate_register
@@ -240,6 +243,7 @@
 	return (status);
 }
 
+#if (!ACPI_REDUCED_HARDWARE)
 /*******************************************************************************
  *
  * FUNCTION:    acpi_hw_clear_acpi_status
@@ -285,7 +289,7 @@
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_hw_get_register_bit_mask
+ * FUNCTION:    acpi_hw_get_bit_register_info
  *
  * PARAMETERS:  register_id         - Index of ACPI Register to access
  *
@@ -658,3 +662,5 @@
 
 	return (status);
 }
+
+#endif				/* !ACPI_REDUCED_HARDWARE */