msm: cpp: Validate frame message before manipulating it

CPP frame message is used to send all frame data
to Microcontroller. It is sent every frame. CPP kernel
driver has to add information to it before transfer it.
The message has to be validated before manipulations.
If it is not valid the message and corresponding frame
are discarded.

Change-Id: Id272eb2296233c66befd015f41f19a9fbc551572
Signed-off-by: Iliya Varadzhakov <ivarad@codeaurora.org>