ion: Revert ION updates for proprietary camera HAL

Squashed commit of the following commits:

Revert "msm: ion: Only return Ion flags in ion_handle_get_flags"

This reverts commit d40fd66600da3e866b50af86ce7f3fec8e21a7d4.

Revert "gpu: ion: fix some missing defines for ion mini upgrade"

This reverts commit 5a062fd2f408dd34c5af60e0b9eb3643aa62384c.

Revert "gpu: ion: move msm-specific ioctls to custom_ioctl"

This reverts commit a94c976b1c12ff78e3b9dd760deca00a15102659.

Revert "gpu: ion: repurpose flags field for heap_mask and caching"

This reverts commit 0356cdd2037050a5994d33c703a10f7652281bcf.

Revert "Revert "ion: restore ics ion_allocation_data structure""

This reverts commit b75661b2d89bf5974654b0145f58eb7409301cda.