ANDROID: GKI: dma-buf: Add support for XXX_cpu_access_umapped ops

Userspace clients will be able to restrict cache maintenance to only
the subset of the dma-buf which is mmap(ed) by setting the
DMA_BUF_SYNC_USER_MAPPED flag when calling the DMA_BUF_IOCTL_SYNC IOCT.

Signed-off-by: Swathi Sridhar <swatsrid@codeaurora.org>

Bug: 150611569
Test: build
(cherry-picked from bbbc80b6)
[surenb: partial cherry-pick from
bbbc80b6 ion : Merge ion changes from ...
to resolve ABI diffs caused by {begin/end}_cpu_access_umapped
dma_buf_ops.
changed dma_buf_end_cpu_access_umapped to be static.]
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: Ic2029c5218ca99330a0e7e6128e12ac29cdd1c08