net: ifb: support BIG TCP packets

Set the driver limit to GSO_MAX_SIZE (512 KB).

This allows the admin/user to set a GSO limit up to this value, to
avoid segmenting too large GRO packets in the netem -> ifb path.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250701084540.459261-1-edumazet@google.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>