ice: split ice_vsi_setup into smaller functions

Main goal is to reuse the same functions in VSI config and rebuild
paths.
To do this split ice_vsi_setup into smaller pieces and reuse it during
rebuild.

ice_vsi_alloc() should only alloc memory, not set the default values
for VSI.
Move setting defaults to separate function. This will allow config of
already allocated VSI, for example in reload path.

The path is mostly moving code around without introducing new
functionality. Functions ice_vsi_cfg() and ice_vsi_decfg() were
added, but they are using code that already exist.

Use flag to pass information about VSI initialization during rebuild
instead of using boolean value.

Co-developed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>