msm: HTC: m7: use Linux kernel style

Change-Id: Ie2e97d300978a89f65982855c769bafe6f6fc37f
msm: HTC: m7: use CAF style memory allocation

* Set SF heap size to 0 when IOMMU is enabled
* Update ION reservation function

Change-Id: I480b30a47c78e4e47eae18ac77a3f52f1460d189