msm: mpq8064: Use ION to alloc driver buffers

Since VCAP is behind IOMMU, in order to get proper address for VCAP
hw to write to driver needs to alloc buffer from ION and not
kzalloc.

Change-Id: I1f4fcc6834d0ea09ba0fc812b301219d35f40721
Signed-off-by: Terence Hampson <thampson@codeaurora.org>