IB/mlx4: Get rid of max_inline_data calculation

The calculation of max_inline_data in set_kernel_sq_size() is bogus,
since it doesn't take into account the fact that inline segments may
not cross a 64-byte boundary, and hence multiple inline segments will
probably need to be used to post large inline sends.

We don't support inline sends for kernel QPs anyway, so there's no
point in doing this calculation anyway, since the field is just zeroed
out a little later.  So just delete the bogus calculation.

Signed-off-by: Roland Dreier <rolandd@cisco.com>