allow chaining for pkcs15-init --store-private-key EC keys
allow chaining for pkcs15-init --store-private-key EC keys

when importing a private key onto a pkcs15 card, if the card does not support
extended APDUs, we need to use chaining to store keys longer than 255 bytes.

While for RSA keys, this check was included, it was missing for EC keys.
This patch adds the SC_APDU_FLAGS_CHAINING flag to apdu.flags if data length is
greater than 255 and the card caps does not include SC_CARD_CAP_APDU_EXT.

Fixes #1747

dengert/OpenSC,frankmorgner/OpenSC,frankmorgner/OpenSC,AktivCo/OpenSC,mouse07410/OpenSC,OpenSC/OpenSC,CardContact/OpenSC,philipWendland/OpenSC,frankmorgner/OpenSC,metsma/OpenSC,AktivCo/OpenSC,philipWendland/OpenSC,mouse07410/OpenSC,AktivCo/OpenSC,rickyepoderi/OpenSC,CardContact/OpenSC,dengert/OpenSC,OpenSC/OpenSC,fabled/OpenSC,LudovicRousseau/OpenSC,Jakuje/OpenSC,frankmorgner/OpenSC,hongquan/OpenSC-main,LudovicRousseau/OpenSC,CardContact/OpenSC,rickyepoderi/OpenSC,hongquan/OpenSC-main,LudovicRousseau/OpenSC,metsma/OpenSC,OpenSC/OpenSC,fabled/OpenSC,hongquan/OpenSC-main,Jakuje/OpenSC,metsma/OpenSC,philipWendland/OpenSC,mouse07410/OpenSC,Jakuje/OpenSC,fabled/OpenSC,dengert/OpenSC,fabled/OpenSC,rickyepoderi/OpenSC,Jakuje/OpenSC