smb: client: make use of smbdirect_connection_grant_recv_credits()

smb: client: make use of smbdirect_connection_grant_recv_credits()

This already calls atomic_add(new_credits, &sc->recv_io.credits.count),
so there's no need to do it in the caller anymore.

Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Long Li <longli@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>