ice: remove period on argument description in ice_for_each_vf

The ice_for_each_vf macros have comments describing the implementation. One
of the arguments has a period on the end, which is not our typical style.
Remove the unnecessary period.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>