NFC: llcp: Implement socket options

Some LLCP services (e.g. the validation ones) require some control over
the LLCP link parameters like the receive window (RW) or the MIU extension
(MIUX). This can only be done through socket options.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

include/uapi/linux/nfc.h

@@ -220,4 +220,8 @@ struct sockaddr_nfc_llcp {
 #define NFC_LLCP_DIRECTION_RX		0x00
 #define NFC_LLCP_DIRECTION_TX		0x01
 
+/* socket option names */
+#define NFC_LLCP_RW   0
+#define NFC_LLCP_MIUX 1
+
 #endif /*__LINUX_NFC_H */