crypto: stm32 - Drop if block with always false condition

stm32_hash_remove() is only called after stm32_hash_probe() succeeded. In
this case platform_set_drvdata() was called with a non-NULL data patameter.

The check for hdev being non-NULL can be dropped because hdev is never NULL
(or something bad like memory corruption happened and then the check
doesn't help any more either).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>