Bug 995202: Pass NCI payload size to callback functions

The NCI payload buffer is limited to 256 bytes, so it can easily
overflow. The callback function for creating NCI payload now
receives a parameter that contains the remaining buffer size.

Signed-off-by: Thomas Zimmermann <tdz@users.sourceforge.net>
Bug 995202: Remove NFC data command from console

This patch removes the command 'data' for reading and writing NFC
data. The command is broken, unused, and probably won't ever be
used. If we need to read or write data, it needs to be done in a
way specific to the involved protocols.

Signed-off-by: Thomas Zimmermann <tdz@users.sourceforge.net>
Bug 995202: Rename LLCP packets to PDUs

The LLCP specification calls individual LLCP messages 'PDUs', so
we should too.

Signed-off-by: Thomas Zimmermann <tdz@users.sourceforge.net>
Bug 995202: Added LLCP SAP constants to NFC emulation

The SAP constants contain magic numbers for the Service Access
Points of LLCP, as defined by the NFC forum.

Signed-off-by: Thomas Zimmermann <tdz@users.sourceforge.net>
Bug 995202: Cleanup NFC buffer reading/writing

This patch adds a nice API around NFC-internal buffers.

Signed-off-by: Thomas Zimmermann <tdz@users.sourceforge.net>