NFC: st95hf: remove set but not used variables 'dev, nfcddev'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/nfc/st95hf/core.c: In function 'st95hf_irq_thread_handler':
drivers/nfc/st95hf/core.c:786:26: warning:
 variable 'nfcddev' set but not used [-Wunused-but-set-variable]

drivers/nfc/st95hf/core.c:784:17: warning:
 variable 'dev' set but not used [-Wunused-but-set-variable]

They are never used since introduction in
commit cab47333 ("NFC: Add STMicroelectronics ST95HF driver")

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>