msm: kgsl: Make switch out of secure more target specific

The generic Adreno code was reaching into the a5xx specific code to
run the critical packets.  This is mostly unnecessary because the
a5xx code is the one that calls into the generic code in the first
place so it is a useless round trip especially for such simple
code. Move the secure switch code into the target specific code.

Change-Id: Ic0dedbadf6d25a0740719cf8ac0ccf8802f4c33e
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>