msm: ipa: prevent string buffer overflows

In WAN ioctls user-supplied data structures
contain string members,but there's no guarantee
they're null-terminated, add the string terminator
to prevent vulnerability of string buffer overflows.

Change-Id: I17c06c94aa619a2cd3a678c495a31541a65a7741
Acked-by: Ashok Vuyyuru <avuyyuru@qti.qualcomm.com>
Signed-off-by: Mohammed Javid <mjavid@codeaurora.org>