nvram: Introduce helper functions for CHRP "system" and "free space" partitions

The "system partition" and "free space" partition layouts are
defined by the CHRP and LoPAPR specification, and used by
OpenBIOS and SLOF. We can re-use this code for other machines
that use OpenBIOS and SLOF, too. So let's make this code independent
from the MAC NVRAM environment and put it into two proper helper
functions.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

include/hw/nvram/chrp_nvram.h

@@ -0,0 +1,24 @@
+/*
+ * Common Hardware Reference Platform NVRAM functions.
+ *
+ * This code is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef CHRP_NVRAM_H
+#define CHRP_NVRAM_H
+
+int chrp_nvram_create_system_partition(uint8_t *data, int min_len);
+int chrp_nvram_create_free_partition(uint8_t *data, int len);
+
+#endif