[PATCH] e1000: No-delay link detection at interface up

Currently after an interface up, the link state is detected 2 seconds later
when the first watchdog timer runs. This patch changes that by triggering
the hardware to generate a link-change interrupt from the up() function
instead. This has the result that the link state gets detected immediately
and without races. This has the potential to speed up booting since a normal
distribution boot process waits for a link before DHCP is attempted.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>