sfc: fix NULL dereferences in ef100_process_design_param()

sfc: fix NULL dereferences in ef100_process_design_param()

Since cited commit, ef100_probe_main() and hence also
 ef100_check_design_params() run before efx->net_dev is created;
 consequently, we cannot netif_set_tso_max_size() or _segs() at this
 point.
Move those netif calls to ef100_probe_netdev(), and also replace
 netif_err within the design params code with pci_err.

Reported-by: Kyungwook Boo <bookyungwook@gmail.com>
Fixes: 98ff4c7c8ac7 ("sfc: Separate netdev probe/remove from PCI probe/remove")
Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Link: https://patch.msgid.link/20250401225439.2401047-1-edward.cree@amd.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>