ice: Remove unnecessary NULL check before dev_put

Since commit b37a4668

 ("netdevice: add the case if dev is NULL"),
dev_put(NULL) is safe, check NULL before dev_put() is not needed.

Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>