e1000e: Check the PCIm state

Complete to commit def4ec6d ("e1000e: PCIm function state support")
Check the PCIm state only on CSME systems. There is no point to do this
check on non CSME systems.
This patch fixes a generation a false-positive warning:
"Error in exiting dmoff"

Fixes: def4ec6d ("e1000e: PCIm function state support")
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>