msm: kgsl: Migrate SCM calls in GPU bus governor

Migrate MSM Adreno Governor TZ interface to upstream SCM driver.

Change-Id: I1c4347d33b6be835f04422918c29e9c627e02874
Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Signed-off-by: Siddharth Gupta <sidgup@codeaurora.org>