NFC: digital: Add missing break in switch statement

There was a missing break making the digital stack configured for
ISO1443 target instead of ISO15693.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>