ion: add hack for IOMMU camera

liboemcamera requests memory from the CAMERA or IOMMU heaps, which
we cannot provide currently. Since we cannot change liboemcamera, remap
to CP_MM heap if CAMERA heap is requested
Adapted from HTC msm8960 kernel

Change-Id: I12b00799b6844d0d09f2c55ad19cf31e556e5bb5