NFC Digital: Add initiator NFC-DEP support

This adds support for NFC-DEP protocol in initiator mode for NFC-A and
NFC-F technologies.

When a target is detected, the process flow is as follow:

For NFC-A technology:
1 - The digital stack receives a SEL_RES as the reply of the SEL_REQ
    command.
2   - If b7 of SEL_RES is set, the peer device is configure for NFC-DEP
      protocol. NFC core is notified through nfc_targets_found().
      Execution continues at step 4.
3   - Otherwise, it's a tag and the NFC core is notified. Detection
      ends.
4 - The digital stacks sends an ATR_REQ command containing a randomly
    generated NFCID3 and the general bytes obtained from the LLCP layer
    of NFC core.

For NFC-F technology:
1 - The digital stack receives a SENSF_RES as the reply of the
    SENSF_REQ command.
2   - If B1 and B2 of NFCID2 are 0x01 and 0xFE respectively, the peer
      device is configured for NFC-DEP protocol. NFC core is notified
      through nfc_targets_found(). Execution continues at s...