NFC: digital: Add Type4A tags support

The definition of DIGITAL_PROTO_NFCA_RF_TECH is modified to support
ISO14443 Type4A tags. Without this change it is not possible to start
polling for ISO14443 Type4A tags from the initiator side.

Signed-off-by: Shikha Singh <shikha.singh@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>