crypto: sun4i-ss - Always use sun4i_tfm_ctx for storing pointer to dev ss

The dev *ss is stored both in sun4i_tfm_ctx and sun4i_req_ctx.
Since this pointer will never be changed during tfm life, it is better
to remove it from sun4i_req_ctx.

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/sunxi-ss/sun4i-ss.h

@@ -163,7 +163,6 @@ struct sun4i_req_ctx {
 	u32 hash[5]; /* for storing SS_IVx register */
 	char buf[64];
 	unsigned int len;
-	struct sun4i_ss_ctx *ss;
 	int flags;
 };