RDMA/srp: Support more than 255 rdma ports

Currently ib_srp module does not support devices with more than 256
ports. Switch from u8 to u32 to fix the problem.

Fixes: 1fb7f897 ("RDMA: Support more than 255 rdma ports")
Reviewed-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Mikhael Goikhman <migo@nvidia.com>
Link: https://lore.kernel.org/r/7d80d8844f1abb3a54170b7259f0a02be38080a6.1663747327.git.leonro@nvidia.com


Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Leon Romanovsky <leon@kernel.org>