NFC: pn533: Fix error return code in pn533_probe()

Fix to return -ENOMEM in the nfc device alloc error handling
case instead of 0, as done elsewhere in this function.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>