ixgbe: Make certain to initialize the fdir_perfect_lock in all cases

This fix makes it so that the fdir_perfect_lock is initialized in all
cases.  This is necessary as the fdir_filter_exit routine will always
attempt to take the lock before inspecting the filter table.

Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>