Fix dl2k constants

The MSSR constants didn't match the reality - bitfield declarations used
to be correct (1000BT_FD - bit 11, 1000BT_HD - bit 10), but enum had
them the other way round.  Went unnoticed until the switch from the
bitfields use to the explicit arithmetics and I hadn't caught that one
when verifying correctness of change...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>