NFC: pn533: Add pn533_abort_cmd procedure

pn533_abort_cmd() aborts last command sent to the controller
and cancels already requested urb.

As ACR122U does not support any mechanism (as ACK for standard
PN533) which aborts last command this cannot be issued for this
device. Otherwise, acr122u will behave in an unstable way.

Signed-off-by: Waldemar Rymarkiewicz <waldemar.rymarkiewicz@tieto.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>