msm: kgsl: Use SHM bridge APIs to register buffer with TZ

Instead of directly allocating memory and registering the
buffers to TZ, use SHM bridge to allocate buffers and
register those buffers to TZ.

Change-Id: Ibdc5a66af432f1fb2c8813b0b3578503f404eefc
Signed-off-by: Urvashi Agrawal <urvaagra@codeaurora.org>
Signed-off-by: Raghu Ananya Arabolu <rarabolu@codeaurora.org>