eth: bnxt: make sure we populate the qcfg defaults on old FW/HW

The driver now depends on the core to tell it what the rx page size
should be for the agg ring. We must populate the ndo_default_qcfg
callback even if we don't support any queue ops.

This fixes:
Oops: divide error: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN
RIP: 0010:bnxt_alloc_rx_page_pool (drivers/net/ethernet/broadcom/bnxt/bnxt.c:3852)

with fw version 225.1.109.0.

Link: https://lore.kernel.org/20250421222827.283737-20-kuba@kernel.org
Fixes: f96e1b35779e ("eth: bnxt: support qcfg provided rx page size")
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20260128193258.125274-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>