nfc: s3fwrn5: Remove unneeded 'ret' variable

The local variable 'ret' can be removed:

  drivers/nfc/s3fwrn5/i2c.c:167:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable]

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>