msm: kgsl: Reset the bus_mod value when power is re-enabled

kgsl_pwrctrl_pwrlevel_change() resets the bus_mod level when the
power level is changed but the power level doesn't get changed
on re-init if constraints are enabled with the net effect of
turning on the bus at a lower level than we would expect.  Reset
bus_mod in  kgsl_pwrctrl_enable() to make sure it always comes
up at the expected level.

Change-Id: Ic0dedbad303cc938d91583b3e3309d232590b975
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
msm: kgsl: Update calculation for graphics IOMMU context IDs

Calculate graphics IOMMU context IDs using the 'label' property
of the device tree node of that context. Context IDs are independent
of the register addresses of the SMMU device and its contexts, which
change for every target.

Change-Id: I16825d7248081997a442d4fb59ca5b04b88e33fd
Signed-off-by: Lokesh Batra <lbatra@codeaurora.org>
Signed-off-by: Lynus Vaz <lvaz@codeaurora.org>