phylib: Detect link on 10G devices correctly

gen10g_startup() had 2 bugs:

1) It had a boolean logic error in checking the MMD mask, and
always checked all of them.

2) It checked devices which don't actually report link state, which
meant that it would never believe the link was fully up.

Fix the boolean logic, and then mask the MMD mask so only link-reporting
devices are checked.

Signed-off-by: Andy Fleming <afleming@freescale.com>
Reported-by: Ed Swarthout <Ed.Swarthout@freescale.com>