crypto: img-hash - Fix variable dereferenced before check 'hdev->req'

crypto: img-hash - Fix variable dereferenced before check 'hdev->req'

[ Upstream commit a435272a208230f3263757c326e3159b52587969 ]

Smatch report warning as follows:

drivers/crypto/img-hash.c:366 img_hash_dma_task() warn: variable
dereferenced before check 'hdev->req'

Variable dereferenced should be done after check 'hdev->req',
fix it.

Fixes: c004c2f51dbc ("crypto: img-hash - Add Imagination Technologies hw hash accelerator")
Fixes: 1731bcf22ff8 ("crypto: img-hash - Fix null pointer exception")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>