IB/srp: Fix completion vector assignment algorithm

IB/srp: Fix completion vector assignment algorithm

Ensure that cv_end is equal to ibdev->num_comp_vectors for the
NUMA node with the highest index. This patch improves spreading
of RDMA channels over completion vectors and thereby improves
performance, especially on systems with only a single NUMA node.
This patch drops support for the comp_vector login parameter by
ignoring the value of that parameter since I have not found a
good way to combine support for that parameter and automatic
spreading of RDMA channels over completion vectors.

Fixes: d92c0da71a35 ("IB/srp: Add multichannel support")
Reported-by: Alexander Schmid <alex@modula-shop-systems.de>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Alexander Schmid <alex@modula-shop-systems.de>
Cc: stable@vger.kernel.org
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>