ACPICA: Fix several pointer casts to avoid possible compile warnings

Fixes warnings with gcc -Wcast-qual flag.

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/exdump.c b/drivers/acpi/acpica/exdump.c
index ec52461..de34463 100644
--- a/drivers/acpi/acpica/exdump.c
+++ b/drivers/acpi/acpica/exdump.c
@@ -418,9 +418,9 @@
 		case ACPI_EXD_REFERENCE:
 
 			acpi_ex_out_string("Class Name",
-					   (char *)
-					   acpi_ut_get_reference_name
-					   (obj_desc));
+					   ACPI_CAST_PTR(char,
+							 acpi_ut_get_reference_name
+							 (obj_desc)));
 			acpi_ex_dump_reference_obj(obj_desc);
 			break;