The values used to represent service type of RC and UD should be
interchanged according to design of hardware. And it's better to define
these types in enumeration than macros.

Link: https://lore.kernel.org/r/1578313276-29080-4-git-send-email-liweihang@huawei.comSigned-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>