staging: gasket: support mapping of dma-bufs.

This allows userspace to pass in dma-buf file descriptors for
mapping in addition to userspace virtual memory pointers,
leaving cache maintenance to the dma-buf exporter and userspace
application.

Bug: 149764192
Change-Id: Iee8b581db0a461fe13ee8712d47d66f8fb16e7c9
Signed-off-by: Jonas Larsson <ljonas@google.com>
4 files changed