ice: Fix stats after PF reset

After a core PF reset, the VFs were showing wrong Rx/Tx stats. This is a
regression in commit 6624e780 ("ice: split ice_vsi_setup into smaller
functions") caused by missing to set "stat_offsets_loaded = false" in the
ice_vsi_rebuild() path.

Fixes: 6624e780

 ("ice: split ice_vsi_setup into smaller functions")
Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>