Roll our own ETHER_ALIGN #define like many other driver do.
Use ETHER_ALIGN to calculate number of segments correctly (actually the same way as FreeBSD and OpenBSD do).
Also use ETHER_ALIGN to correctly adjust new mbufs.
This makes the driver finally work. Tested by Jochen Kunz:
ping -nf 192.168.2.1
PING 192.168.2.1 (192.168.2.1): 56 data bytes

----192.168.2.1 PING Statistics----
28949 packets transmitted, 28949 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.157/0.364/2.272/0.023 ms
  2710.6 packets/sec sent,  2710.6 packets/sec received

XXX Shouldn't if_ether.h provide ETHER_ALIGN instead of defining it in all drivers?

(cegger)