e1000e: Remove the runtime suspend restriction on CNP+

e1000e: Remove the runtime suspend restriction on CNP+

Although there is platform issue of runtime suspend support
on CNP, it would be more flexible to let the user decide whether
to disable runtime or not because:
1. This can be done in userspace via
   echo on > /sys/devices/pci0000\:00/0000\:00\:1f.d/power/control
2. More and more NICs would support runtime suspend, disabling the
   runtime suspend on them by default would impact the validation.

Only disable runtime suspend on CNP in case of any user space regression.

Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>