pal: validate stream handle in pal server wrapper

This validates if pal client passes valid stream
handle to server, which is to avoid arbitrary
dereference of handle pointers.

Change-Id: I419f803e232c994f2d9865ba40f75601f6e41f0c
(cherry picked from commit e076162fec4e20948bdae29c091392b1ac93e08c)
2 files changed