jme: GHC register control fix for new hardware

Due to the hardware design, except the first chip on the market,
other chips needs to setup the clock source for MAC processor
implicitly through Global Host Control Register(GHC).
(Strange design huh?)

10/100M uses the PCI-E as clock source, and 1G uses GPHY.

And I reordered the code a little, to make it easier to read.

Found-by: "Ethan" <ethanhsiao@jmicron.com>
Fixed-by: "akeemting" <akeem@jmicron.com>
Signed-off-by: "Guo-Fu Tseng" <cooldavid@cooldavid.org>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>