sungem: fix multicast filter CRC calculation

sungem: fix multicast filter CRC calculation

From the Linux sungem driver, we know that the multicast filter CRC is
implemented using ether_crc_le() which isn't the same as calling zlib's
crc32() function (the zlib implementation requires a complemented initial value
and also returns the complemented result).

Fix the multicast filter by simply using the new net_crc32_le() function.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>