iommu: msm: Add Tracepoints to msm_iommu_pagetable.c

Add trace events to kmem.h and set up trace points in iommu
pagetable to keep track of what size pages we are allocate.

Change-Id: I6b80e0c652046a513808c8e3ae7dbce6510ba20d
Signed-off-by: Adrian Alexei <aalexei@codeaurora.org>