crypto: drop unnecessary return statements

Fix checkpatch.pl warnings:

WARNING: void function return statements are not generally useful
FILE: crypto/rmd128.c:218:
FILE: crypto/rmd160.c:261:
FILE: crypto/rmd256.c:233:
FILE: crypto/rmd320.c:280:
FILE: crypto/tcrypt.c:385:
FILE: drivers/crypto/ixp4xx_crypto.c:538:
FILE: drivers/crypto/marvell/cesa.c:81:
FILE: drivers/crypto/ux500/cryp/cryp_core.c:1755:

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/rmd320.c

@@ -275,8 +275,6 @@ static void rmd320_transform(u32 *state, const __le32 *in)
 	state[7] += ccc;
 	state[8] += ddd;
 	state[9] += eee;
-
-	return;
 }
 
 static int rmd320_init(struct shash_desc *desc)