Partial implementation of "display: Clean up gralloc"

Make the new display API flags available under QCOM_BSP

Originally...
* Remove pmem and ashmem implementations
* Remove usage of RefBase
* Reduce log verbosity

Change-Id: If8ef543d236e5305bd5430f4f9c62c51b3a13787
display: Add display metadata in buffer handle

Allocate extra space for metadata in buffer handles
Provide api to map this space in client process and set the metadata

Change-Id: I8bca8448670d4aa88d439320faf402dae30458f8
(cherry picked from commit 13933c5ea7b20a6862cefef5f97d0369cbc12b00)