ice: Fix a memory leak in an error handling path in 'ice_pf_dcb_cfg()'

If this 'kzalloc()' fails we must free some resources as in all the other
error handling paths of this function.

Fixes: 348048e7 ("ice: Implement iidc operations")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>