msm: kgsl: Retry setting the SMMU aperture on A6XX targets

Instead of depending on qcom_scm_kgsl_set_smmu_aperture_available
to set the SMMU aperture, we only set the aperture on A6XX targets.
Also retry setting the SMMU aperture if qcom_scm_kgsl_set_smmu_aperture
returns -EBUSY.

Change-Id: I61028e2681342befcdc40b5a11e3f6da41e85a9a
Signed-off-by: Raghu Ananya Arabolu <rarabolu@codeaurora.org>