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

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 6f5e395..2c626e8 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -466,7 +466,7 @@
 
 	info = buffer.pointer;
 	if (!(info->valid & ACPI_VALID_HID)) {
-		acpi_os_free(buffer.pointer);
+		kfree(buffer.pointer);
 		return AE_ERROR;
 	}
 
@@ -475,7 +475,7 @@
 	    (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
 		status = AE_ERROR;
 
-	acpi_os_free(buffer.pointer);
+	kfree(buffer.pointer);
 	return status;
 }