staging: android: ion: Remove ION_FLAG_CACHED_NEEDS_SYNC

The flag ION_FLAG_CACHED_NEEDS_SYNC isn't used anymore. Remove it.

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>