[SUNGEM]: PHY updates & pause fixes (#2)

This patch adds support for a few more PHYs used by Apple and fixes
advertising and detecting of Pause (we were missing setting the bit in
MII_ADVERTISE and weren't testing in LPA for all PHYs).

Note that I currently only advertise pause, not asymetric pause. I
don't know for sure the details there, I suppose I should read a bit
more 802.3 references, and I don't now what sungem is capable of, but
I noticed the PCS code (originated from you) does the same.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David S. Miller <davem@davemloft.net>