RDMA/mlx5: Handle errors returned from mlx5r_ib_rate()

RDMA/mlx5: Handle errors returned from mlx5r_ib_rate()

In function create_ib_ah() the following line attempts
to left shift the return value of mlx5r_ib_rate() by 4
and store it in the stat_rate_sl member of av:

However the code overlooks the fact that mlx5r_ib_rate()
may return -EINVAL if the rate passed to it is less than
IB_RATE_2_5_GBPS or greater than IB_RATE_800_GBPS.

Because of this, the code may invoke undefined behaviour when
shifting a signed negative value when doing "-EINVAL << 4".

To fix this check for errors before assigning stat_rate_sl and
propagate any error value to the callers.

Fixes: c534ffda781f ("RDMA/mlx5: Fix AH static rate parsing")
Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
Link: https://patch.msgid.link/20250304140246.205919-1-qasdev00@gmail.com
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>