We can remove the NULL check here.  It triggers a Smatch warning because
list_first_entry() never is NULL and people who check for it normally
intend to check for list_empty() instead.  In these cases however,
we've already verified that the lists are not empty.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

This is needed for USB.

Based on code by Kevin Fang.
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>