[qca-nss-clients] xfrm: Fix SA and Tunnel init.

1. Fix nss_ipsec_xfrm_sa_init_crypto(), when algo is of type
aead. Also, fix null cipher support.
2. Correctly handle missing IPv4 route condition during 
nss_ipsec_xfrm_tunnel_alloc().

Signed-off-by: Neelansh Mittal <neelanshm@codeaurora.org>
Change-Id: I3673bfbdd6faaaa5c858870839309bde93a587e3
2 files changed