Fix sparse warning:

drivers/crypto/ccp/ccp-crypto-rsa.c:251:5:
 warning: symbol 'ccp_register_rsa_alg' was not declared. Should it be static?
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>