i40e: do not enter PHY debug mode while setting LEDs behaviour

Previous implementation of LED set/get functions required to enter
PHY debug mode, in order to prevent access to it from FW and SW at
the same time. Reset of all ports was a unwanted side effect.

Signed-off-by: Mariusz Stachura <mariusz.stachura@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>