e1000e: fix typo in definition of E1000_CTRL_EXT_FORCE_SMBUS

This define is needed by i217.

Reported-by: Bjorn Mork <bjorn@mork.no>
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>