qcacmn: Return gracefully if ingress device is NULL
If the ingress net device is NULL, return gracefully
from the API to check if the skb is from rmnet
Change-Id: I81b8cea7f311fe581e83f2310155b83b28f2fd32
CRs-Fixed: 3445050
Pavankumar Nandeshwar%!s(int64=2) %!d(string=hai) anos