MIPS: ath79: add common WMAC device for AR913X based boards

Add common platform_device and helper code to make the registration
of the built-in wireless MAC easier on the Atheros AR9130/AR9132
based boards. Also register the WMAC device on the AR81 board.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Imre Kaloz <kaloz@openwrt.org>,
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1962/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/ath79/dev-ar913x-wmac.h b/arch/mips/ath79/dev-ar913x-wmac.h
new file mode 100644
index 0000000..579d562
--- /dev/null
+++ b/arch/mips/ath79/dev-ar913x-wmac.h
@@ -0,0 +1,17 @@
+/*
+ *  Atheros AR913X SoC built-in WMAC device support
+ *
+ *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ */
+
+#ifndef _ATH79_DEV_AR913X_WMAC_H
+#define _ATH79_DEV_AR913X_WMAC_H
+
+void ath79_register_ar913x_wmac(u8 *cal_data);
+
+#endif /* _ATH79_DEV_AR913X_WMAC_H */