msm: secure_buffer: Add SPSS_SP vmid

Add support for content protection for ION
memory allocated to SPSS through user process.

Change-Id: I1aa37717c02a5b96468d16ec1a26bb2ee7020e74
Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org>
[lmark@codeaurora.org: don't include ION changes as these
 will be applied separately]
Signed-off-by: Liam Mark <lmark@codeaurora.org>