crypto: akcipher - pass instance to crypto_grab_akcipher()

Initializing a crypto_akcipher_spawn currently requires:

1. Set spawn->base.inst to point to the instance.
2. Call crypto_grab_akcipher().

But there's no reason for these steps to be separate, and in fact this
unneeded complication has caused at least one bug, the one fixed by
commit 6db43410179b ("crypto: adiantum - initialize crypto_spawn::inst")

So just make crypto_grab_akcipher() take the instance as an argument.

To keep the function call from getting too unwieldy due to this extra
argument, also introduce a 'mask' variable into pkcs1pad_create().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/akcipher.c b/crypto/akcipher.c
index 7d5cf49..84ccf9b 100644
--- a/crypto/akcipher.c
+++ b/crypto/akcipher.c
@@ -90,9 +90,11 @@ static const struct crypto_type crypto_akcipher_type = {
 	.tfmsize = offsetof(struct crypto_akcipher, base),
 };
 
-int crypto_grab_akcipher(struct crypto_akcipher_spawn *spawn, const char *name,
-			 u32 type, u32 mask)
+int crypto_grab_akcipher(struct crypto_akcipher_spawn *spawn,
+			 struct crypto_instance *inst,
+			 const char *name, u32 type, u32 mask)
 {
+	spawn->base.inst = inst;
 	spawn->base.frontend = &crypto_akcipher_type;
 	return crypto_grab_spawn(&spawn->base, name, type, mask);
 }