Make all private functions in e_afalg.c static

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5270)

engines/e_afalg.c

@@ -79,7 +79,7 @@ static int afalg_create_sk(afalg_ctx *actx, const char *ciphertype,
 static int afalg_destroy(ENGINE *e);
 static int afalg_init(ENGINE *e);
 static int afalg_finish(ENGINE *e);
-const EVP_CIPHER *afalg_aes_cbc(int nid);
+static const EVP_CIPHER *afalg_aes_cbc(int nid);
 static cbc_handles *get_cipher_handle(int nid);
 static int afalg_ciphers(ENGINE *e, const EVP_CIPHER **cipher,
                          const int **nids, int nid);
@@ -195,7 +195,7 @@ static int afalg_setup_async_event_notification(afalg_aio *aio)
     return 1;
 }
 
-int afalg_init_aio(afalg_aio *aio)
+static int afalg_init_aio(afalg_aio *aio)
 {
     int r = -1;
 
@@ -215,7 +215,7 @@ int afalg_init_aio(afalg_aio *aio)
     return 1;
 }
 
-int afalg_fin_cipher_aio(afalg_aio *aio, int sfd, unsigned char *buf,
+static int afalg_fin_cipher_aio(afalg_aio *aio, int sfd, unsigned char *buf,
                                 size_t len)
 {
     int r;
@@ -658,7 +658,7 @@ static cbc_handles *get_cipher_handle(int nid)
     }
 }
 
-const EVP_CIPHER *afalg_aes_cbc(int nid)
+static const EVP_CIPHER *afalg_aes_cbc(int nid)
 {
     cbc_handles *cipher_handle = get_cipher_handle(nid);
     if (cipher_handle->_hidden == NULL