crypto: amlogic - Fix unnecessary check in meson_crypto_probe()

The function meson_crypto_probe() is only called with an openfirmware
platform device. Therefore there is no need to check that the passed
in device is NULL.

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>