RDMA/usnic: Fix spelling mistake "transistion" -> "transition"

There is a spelling mistake in a usnic_err error message. Fix it.

Link: https://lore.kernel.org/r/20200805141459.23069-1-colin.king@canonical.com


Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>