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

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 00b0728..7d92f73 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -171,7 +171,7 @@
 	}
 
       end:
-	acpi_os_free(buffer.pointer);
+	kfree(buffer.pointer);
 
 	if (!result)
 		(*bif) = (struct acpi_battery_info *)data.pointer;
@@ -231,7 +231,7 @@
 	}
 
       end:
-	acpi_os_free(buffer.pointer);
+	kfree(buffer.pointer);
 
 	if (!result)
 		(*bst) = (struct acpi_battery_status *)data.pointer;