ARM: dts: msm: Correct CB label on msm8937

 Couple of CB labels were wrong in APPS SMMU
 on msm8937. This would have resulted in
 wrong CB being returned to master on calling
 msm_iommu_get_ctx. Fix the labels so that
 right CB is returned.

Change-Id: Ia7f0ef62d9f558d67d13df10fa20a20d019e805d
Signed-off-by: Susheel Khiani <skhiani@codeaurora.org>