So far we implemented only one round of "Send the APDU, get SW=61xx,
call GET RESPONSE". This permitted us to receive only data up to 256
bytes.
Let's extend that to doing multiple rounds, concatenating the result.
This allows us to obtain arbitrary-length data from the card.
See Annex C.1 of ETSI TS 102 221 for examples showing multiple 61xx
iterations.
Change-Id: Ib17da655aa0b0eb203c29dc92690c81bd1300778
Closes: OS#6287