msm: kgsl: Set the CP_APRIV_CNTL for A650

Prior to a650, packets like CP_INIT, SET_SECURE_MODE were executable
out of ringbuffer.From a650 onwards, these packets will be dropped by
CP if rbprivlevel bit is not set in CP_APRIV_CNTL.So set this bit
unconditionally so that CP doesn't drop these packets when it
sees them in the ringbuffer.

Change-Id: Ic29a17988d606b865389ca365eff69d51c73d594
Signed-off-by: Urvashi Agrawal <urvaagra@codeaurora.org>