Fix following warnings:
[examples/pn53x-tamashell.c:162]: (warning) scanf without field width limits can crash with huge input data
[libnfc/drivers/acr122_pcsc.c:261]: (warning) scanf without field width limits can crash with huge input data
[libnfc/drivers/acr122s.c:441]: (warning) scanf without field width limits can crash with huge input data
[libnfc/drivers/arygon.c:210]: (warning) scanf without field width limits can crash with huge input data
[libnfc/drivers/arygon.c:522]: (warning) scanf without field width limits can crash with huge input data
[libnfc/drivers/pn532_uart.c:187]: (warning) scanf without field width limits can crash with huge input data
[utils/nfc-relay-picc.c:176]: (warning) scanf without field width limits can crash with huge input data