Ignore junk values received for PHY status reg

At times, we read 0xFFFF from the PHY 4 status register. This is clearly
not a valid value and might cause issues further down the road. Bit 5 of
this register indicates whether auto negotiation has completed. If we
interpret 0xFFFF this way, then we would wrongly assume that auto
negotiation has completed.

Change-Id: I5a6b8cd0c9dc1615a9574dbe9a0d89d2c47176e8
1 file changed