Add constant for FCS/CRC length (frame check sequence)

About a dozen drivers that have some form of crc checksumming or offloading
use this constant, warranting a global define for it.

Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
1 file changed