net: enetc: register XDP RX queues with frag_size

net: enetc: register XDP RX queues with frag_size

At the time when bpf_xdp_adjust_tail() gained support for non-linear
buffers, ENETC was already generating this kind of geometry on RX, due
to its use of 2K half page buffers. Frames larger than 1472 bytes
(without FCS) are stored as multi-buffer, presenting a need for multi
buffer support to work properly even in standard MTU circumstances.

Allow bpf_xdp_frags_increase_tail() to know the allocation size of paged
data, so it can safely permit growing the tailroom of the buffer from
XDP programs.

Fixes: bf25146a5595 ("bpf: add frags support to the bpf_xdp_adjust_tail() API")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Wei Fang <wei.fang@nxp.com>
Link: https://patch.msgid.link/20250417120005.3288549-2-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>