ice: destroy flow director filter mutex after releasing VSIs

Currently fdir_fltr_lock is accessed in ice_vsi_release_all() function
after it is destroyed. Instead destroy mutex after ice_vsi_release_all.

Fixes: 40319796 ("ice: Add flow director support for channel mode")
Signed-off-by: Sudheer Mogilappagari <sudheer.mogilappagari@intel.com>
Tested-by: Bharathi Sreenivas <bharathi.sreenivas@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>