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>

drivers/crypto/ixp4xx_crypto.c

@@ -534,7 +534,6 @@ static void release_ixp_crypto(struct device *dev)
 			NPE_QLEN_TOTAL * sizeof( struct crypt_ctl),
 			crypt_virt, crypt_phys);
 	}
-	return;
 }
 
 static void reset_sa_dir(struct ix_sa_dir *dir)