Revert "board-jena: reduce the size of pmem_adsp heap"
Actually, we're not using the ION camera heap.
We use PMEM ADSP, so any multimedia request has to be sent to it.
Sending multimedia requests to ION heap will fail as qdsp is working with PMEM.
For this reason we've *libmemalloc* with PMEM ADSP support and legacy(PMEM) OMXs.

This reverts commit aceeb8b6a7364572758579302cd1ad91c858633f.