crypto: stm32 - drop pointless static qualifier in stm32_hash_remove()

There is no need to have the struct stm32_hash_dev *hdev static
since new value always be assigned before use it.

Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>