RDMA/bnxt_re: Remove FMR leftovers

The bnxt_re_fmr struct is never referenced and the max_fmr items
in bnxt_qplib_dev_attr are never read.

Link: https://lore.kernel.org/r/6-v3-f58e6669d5d3+2cf-fmr_removal_jgg@mellanox.com


Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>