ieee802154: cc2520: adds driver for TI CC2520 radio

This patch adds the driver support for the cc2520 radio.

Driver support:
	- Tx and Rx of IEEE-802.15.4 packets
	- Energy Detection on channel
	- Setting the Channel for the radio. [b/w 11 - 26 channels]
	- Start and Stop the radio
	- h/w address filtering
Signed-off-by: NVarka Bhadram <varkab@cdac.in>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/spi/cc2520.h

+/* Header file for cc2520 radio driver
+ *
+ * Copyright (C) 2014 Varka Bhadram <varkab@cdac.in>
+ *                    Md.Jamal Mohiuddin <mjmohiuddin@cdac.in>
+ *                    P Sowjanya <sowjanyap@cdac.in>
+ *
+ * This program 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.
+ *
+ */
+
+#ifndef __CC2520_H
+#define __CC2520_H
+
+struct cc2520_platform_data {
+	int fifo;
+	int fifop;
+	int cca;
+	int sfd;
+	int reset;
+	int vreg;
+};
+
+#endif