NFC: st21nfcb: Retry i2c_master_send if it returns a negative value

i2c_master_send may return many negative values different than
-EREMOTEIO.
In case an i2c transaction is NACK'ed, on raspberry pi B+
kernel 3.18, -EIO is generated instead.

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