Changes

firmware: sniffer: do not drop maximum-length ATRs

7816-3 8.1/8.2.1 allow TS plus 32 bytes.
atr_i is a byte count, not an index, process_byte_atr() guards its own
store with the same condition before incrementing, so atr_i reaches 33.

Change-Id: Ic8398cbefc0b522946b6470fd0268fa70662dab1