When the peer in an NFC-DEP exchange has a
packet to send that is larger than the local
maximum payload, it sets the 'MI' bit in the
'I' PDU.  This indicates that NFC-DEP chaining
is to occur.

When such a PDU is received, the local side
responds with an 'ACK' PDU and this continues
until the peer sends an 'I' PDU with the 'MI'
bit cleared.  This indicates that the chaining
sequence is complete and the entire packet has
been transferred.

Receiving chained PDUs is currently not supported
by the digital layer so add that support.  When a
chaining sequence is initiated by the peer, the
digital layer will allocate an skb large enough
to hold 8 maximum sized frame payloads.  The maximum
payload can range from 64 to 254 bytes so 8 * 254 =
2032 seems like a reasonable compromise between
potentially wasting memory and constantly reallocating
new, larger skbs.
Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>