crypto: img-hash - Fix set_reqsize call

Properly allocate enough memory to respect the fallback.

Signed-off-by: Will Thomas <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/img-hash.c

···
 	}
 	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
 				 sizeof(struct img_hash_request_ctx) +
+				 crypto_ahash_reqsize(ctx->fallback) +
 				 IMG_HASH_DMA_THRESHOLD);
 
 	return 0;