ice: store VF's pci_dev ptr in ice_vf

Extend struct ice_vf by vfdev.
Calculation of vfdev falls more nicely into ice_create_vf_entries().

Caching of vfdev enables simplification of ice_restore_all_vfs_msi_state().

Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Co-developed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Signed-off-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>