Coverity reports that pointers ip and ip6 may be dereferenced
with null value. This patch fixes this.
Coverity issue: 365549, 365551
Fixes: 8f685ec2d5 ("crypto/octeontx2: support AES-CBC SHA1-HMAC")
Signed-off-by: Ankur Dwivedi <adwivedi@marvell.com>