ice: Rename build_ctob to ice_build_ctob

To make the function easier to identify as being part of the ice driver,
prepend ice to the function name.

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>