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/utxface.c b/drivers/acpi/acpica/utxface.c
index 644e8c8..afa94f5 100644
--- a/drivers/acpi/acpica/utxface.c
+++ b/drivers/acpi/acpica/utxface.c
@@ -145,6 +145,8 @@
 
 	ACPI_FUNCTION_TRACE(acpi_enable_subsystem);
 
+#if (!ACPI_REDUCED_HARDWARE)
+
 	/* Enable ACPI mode */
 
 	if (!(flags & ACPI_NO_ACPI_ENABLE)) {
@@ -169,6 +171,7 @@
 		ACPI_WARNING((AE_INFO, "Could not map the FACS table"));
 		return_ACPI_STATUS(status);
 	}
+#endif				/* !ACPI_REDUCED_HARDWARE */
 
 	/*
 	 * Install the default op_region handlers. These are installed unless
@@ -184,7 +187,7 @@
 			return_ACPI_STATUS(status);
 		}
 	}
-
+#if (!ACPI_REDUCED_HARDWARE)
 	/*
 	 * Initialize ACPI Event handling (Fixed and General Purpose)
 	 *
@@ -220,6 +223,7 @@
 			return_ACPI_STATUS(status);
 		}
 	}
+#endif				/* !ACPI_REDUCED_HARDWARE */
 
 	return_ACPI_STATUS(status);
 }