net/e1000/base: modify flow control setup

net/e1000/base: modify flow control setup

Customers had a problem with large pings after connected standby.
This is due to the requirement of maintaining link after CS - the driver
blocks resets during "AdapterStart" and skips flow control setup.
Added condition in e1000_setup_link_ich8lan.c function that always setup
flow control, and setup physical interface only when no need to block
resets.

Signed-off-by: Nir Efrati <nir.efrati@intel.com>
Signed-off-by: Guinan Sun <guinanx.sun@intel.com>
Reviewed-by: Wei Zhao <wei.zhao1@intel.com>