NFC: pn533: Fix missing parenthesis

This is a quite critical patch as it fixes potential reference to
undefined general_bytes which were never set correctly on target
activation due to missing parenthesis.

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