NFC: Reserve tx head and tail room

We can have the NFC core layer allocating the tx head and tail
room for the drivers and avoid 1 or more SKBs copy on write on
the Tx path.

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 330a4c5..c525e0b 100644
--- a/include/linux/nfc.h
+++ b/include/linux/nfc.h
@@ -123,4 +123,6 @@
 #define NFC_SOCKPROTO_RAW	0
 #define NFC_SOCKPROTO_MAX	1
 
+#define NFC_HEADER_SIZE 1
+
 #endif /*__LINUX_NFC_H */