ice: remove splitting MSI-X between features

With dynamic approach to alloc MSI-X there is no sense to statically
split MSI-X between PF features.

Splitting was also calculating needed MSI-X. Move this part to separate
function and use as max value.

Remove ICE_ESWITCH_MSIX, as there is no need for additional MSI-X for
switchdev.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com>
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>