ice: Store number of functions for the device

Store the number of functions the device has and use this number when
setting safe mode capabilities instead of calculating it.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Co-developed-by: Kevin Scott <kevin.c.scott@intel.com>
Signed-off-by: Kevin Scott <kevin.c.scott@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>