add msm8660 support

* straight copy and paste from msm8960
msm8660: ifdef liblight
msm8660: add compat finish symbol for ctx
msm8660: activate GENLOCK support
msm8660: libgralloc: remove fallback to IOMMU heap
msm8660: libgralloc: assign a proper alloc size in some corner cases
msm8660: libgralloc: include pmem kernel header for OLD_ION_API compliance
msm8660: libhwcomposer: disable base pipe
msm8660: libhwcomposer: disable fallback to copybit when mdpcomp fails