crypto: ccp - Fix non static symbol warning

Fixes the following sparse warning:

drivers/crypto/ccp/ccp-dev.c:44:6: warning:
 symbol 'ccp_error_codes' was not declared. Should it be static?
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/ccp/ccp-dev.c

@@ -41,7 +41,7 @@ struct ccp_tasklet_data {
 };
 
 /* Human-readable error strings */
-char *ccp_error_codes[] = {
+static char *ccp_error_codes[] = {
 	"",
 	"ERR 01: ILLEGAL_ENGINE",
 	"ERR 02: ILLEGAL_KEY_ID",