IB/qib: Remove unused cnt variable

IB/qib: Remove unused cnt variable

clang with W=1 reports
drivers/infiniband/hw/qib/qib_file_ops.c:487:20: error: variable
  'cnt' set but not used [-Werror,-Wunused-but-set-variable]
        u32 tid, ctxttid, cnt, limit, tidcnt;
                          ^
drivers/infiniband/hw/qib/qib_file_ops.c:1771:9: error: variable
  'cnt' set but not used [-Werror,-Wunused-but-set-variable]
        int i, cnt = 0, maxtid = ctxt_tidbase + dd->rcvtidcnt;
               ^
This variable is not used so remove it.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20230330235800.1845815-1-trix@redhat.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>