NFC: Add device powered netlink attribute

For user space to know if a device is up or down.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/linux/nfc.h b/include/linux/nfc.h
index b4999ab..39c1fcf 100644
--- a/include/linux/nfc.h
+++ b/include/linux/nfc.h
@@ -107,6 +107,7 @@
 	NFC_ATTR_TARGET_SENSF_RES,
 	NFC_ATTR_COMM_MODE,
 	NFC_ATTR_RF_MODE,
+	NFC_ATTR_DEVICE_POWERED,
 /* private: internal use only */
 	__NFC_ATTR_AFTER_LAST
 };