ACPI: delete acpi_os_free(), use kfree() directly

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/system.c b/drivers/acpi/system.c
index c90bd2f..c3bb7faa 100644
--- a/drivers/acpi/system.c
+++ b/drivers/acpi/system.c
@@ -86,7 +86,7 @@
 
 	res = simple_read_from_buffer(buffer, count, ppos,
 				      dsdt.pointer, dsdt.length);
-	acpi_os_free(dsdt.pointer);
+	kfree(dsdt.pointer);
 
 	return res;
 }
@@ -113,7 +113,7 @@
 
 	res = simple_read_from_buffer(buffer, count, ppos,
 				      fadt.pointer, fadt.length);
-	acpi_os_free(fadt.pointer);
+	kfree(fadt.pointer);
 
 	return res;
 }