RDMA/nes: remove redundant check on udata

The non-null check on udata is redundant as this check was performed just
a few statements earlier and the check is always true as udata must be
non-null at this point. Remove redundant the check on udata and the
redundant else part that can never be executed.

Detected by CoverityScan, CID#1477317 ("Logically dead code")

Fixes: 89944450

 ("IB/{hw,sw}: Remove 'uobject->context' dependency in object creation APIs")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>