Revert "fdmem: always map dmabuf with PROT_WRITE"

Will be replaced with a similar change.

BUG: 148221549

This reverts commit 221717a7f60b4793007077e3aa7fe29bc1dc11eb.

Change-Id: I52f3ecaafcd58fe95318f6229f1c81508fdd0c8c
3 files changed