drm/msm: remove duplicated code from a6xx_create_address_space

The function a6xx_create_address_space() is mostly a copy of
adreno_iommu_create_address_space() with added quirk setting. Rework
these two functions to be a thin wrappers around a common helper.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/509614/
Link: https://lore.kernel.org/r/20221102175449.452283-3-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>