tg3: Fix supporting flowctrl code

This patch does three things. It modifies tg3_setup_flow_control() to use the administrator requested flow control settings if autonegotiation is turned off. It slightly modifies the tg3_setup_fiber_mii_phy() function to account for this new use case. And finally, it does the same for tg3_setup_copper_phy().

The copper modifications are more than a small multi-line change. The new code makes an attempt to avoid a link renegotiation if the link is active at half duplex and the only difference between the current advertised settings and requested advertised settings is the flow control advertisements.

Signed-off-by Matt Carlson <[email protected]>

Signed-off-by Michael Chan <[email protected]>