msm: ipa: gsb: Validate iface handle

Decode wrong iface handle from mux header of
corrupted packet, leads to invoke invalid index
of iface's tx_dp_notify, in turn leads to
segmentation fault.

So, validate the iface handle which is received
from status packet's mux header before invoking
tx_dp_notify of iface handle.

Change-Id: I21fd54a5c07d25f69a81d67eb4482ea1cc135ea9
Signed-off-by: Mohammed <mjavid@codeaurora.org>