ACPICA: All: const keyword changes across the ACPICA source

ACPICA commit a240cbb93647bddf525b3daf6e9d31b8b9bca34e

Integrated most changes proposed by net_BSD.
>From joerg@net_BSD.org (Joerg Sonnenberger)
ACPICA BZ 732.

Link: https://github.com/acpica/acpica/commit/a240cbb9
Link: https://bugs.acpica.org/show_bug.cgi?id=732
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/acpica/acstruct.h b/drivers/acpi/acpica/acstruct.h
index b3b386e..6235642 100644
--- a/drivers/acpi/acpica/acstruct.h
+++ b/drivers/acpi/acpica/acstruct.h
@@ -184,7 +184,7 @@
 	/* The first 3 elements are passed by the caller to acpi_ns_evaluate */
 
 	struct acpi_namespace_node *prefix_node;	/* Input: starting node */
-	char *relative_pathname;	/* Input: path relative to prefix_node */
+	const char *relative_pathname;	/* Input: path relative to prefix_node */
 	union acpi_operand_object **parameters;	/* Input: argument list */
 
 	struct acpi_namespace_node *node;	/* Resolved node (prefix_node:relative_pathname) */