NFC: dts: st21nfcb: Fix compatible string spelling to follow other drivers

Other drivers are following the following compatible string format for dts:
s/_/-/

Because some devices may still use the previous string, the new corrected
string is added to the of_device_id table.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>