Bluetooth: EFS: implement L2CAP config pending state

Bluetooth: EFS: implement L2CAP config pending state

Add L2CAP Config Pending state for EFS. Currently after receiving
Config Response Pending respond with Config Response Success.

...
> ACL data: handle 1 flags 0x02 dlen 16
    L2CAP(s): Connect rsp: dcid 0x0040 scid 0x0040 result 0 status 0
      Connection successful
> ACL data: handle 1 flags 0x02 dlen 45
    L2CAP(s): Config req: dcid 0x0040 flags 0x00 clen 33
      RFC 0x03 (Enhanced Retransmission, TxWin 63, MaxTx 3, RTo 0, MTo 0, MPS 1009)
      EFS (Id 0x01, SerType Best Effort, MaxSDU 0xffff, SDUitime 0xffffffff,
          AccLat 0xffffffff, FlushTO 0x0000ffff)
< ACL data: handle 1 flags 0x00 dlen 45
    L2CAP(s): Config req: dcid 0x0040 flags 0x00 clen 33
      RFC 0x03 (Enhanced Retransmission, TxWin 63, MaxTx 3, RTo 0, MTo 0, MPS 498)
      EFS (Id 0x01, SerType Best Effort, MaxSDU 0xffff, SDUitime 0xffffffff,
          AccLat 0xffffffff, FlushTO 0x0000ffff)
< ACL data: handle 1 flags 0x00 dlen 47
    L2CAP(s): Config rsp: scid 0x0040 flags 0x00 result 4 clen 33
      Pending
      MTU 672
      RFC 0x03 (Enhanced Retransmission, TxWin 63, MaxTx 3, RTo 2000, MTo 12000, MPS 498)
      EFS (Id 0x01, SerType Best Effort, MaxSDU 0xffff, SDUitime 0xffffffff,
          AccLat 0xffffffff, FlushTO 0x0000ffff)
> ACL data: handle 1 flags 0x02 dlen 47
    L2CAP(s): Config rsp: scid 0x0040 flags 0x00 result 4 clen 33
      Pending
      MTU 672
      RFC 0x03 (Enhanced Retransmission, TxWin 63, MaxTx 3, RTo 2000, MTo 12000, MPS 498)
      EFS (Id 0x01, SerType Best Effort, MaxSDU 0xffff, SDUitime 0xffffffff,
          AccLat 0xffffffff, FlushTO 0x0000ffff)
> ACL data: handle 1 flags 0x02 dlen 14
    L2CAP(s): Config rsp: scid 0x0040 flags 0x00 result 0 clen 0
      Success
< ACL data: handle 1 flags 0x00 dlen 14
    L2CAP(s): Config rsp: scid 0x0040 flags 0x00 result 0 clen 0
      Success
< ACL data: handle 1 flags 0x00 dlen 510
    L2CAP(d): cid 0x0040 len 506 ext_ctrl 0x00010000 fcs 0xebe0 [psm 4113]
      I-frame: Start (len 672) TxSeq 0 ReqSeq 0
...

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>