net: bcmgenet: Fix FCS generation for fragmented skbuffs

The flag DMA_TX_APPEND_CRC was only written to the first DMA descriptor
in the TX path, where each descriptor corresponds to a single skbuff
fragment (or the skbuff head). This led to packets with no FCS appearing
on the wire if the kernel allocated the packet in fragments, which would
always happen when using PACKET_MMAP/TPACKET (cf. tpacket_fill_skb() in
net/af_packet.c).

Fixes: 1c1008c7

 ("net: bcmgenet: add main driver file")
Signed-off-by: Adrian Cinal <adriancinal1@gmail.com>
Acked-by: Doug Berger <opendmb@gmail.com>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20231228135638.1339245-1-adriancinal1@gmail.com


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