Partial revert "Remove ioprio_get(2) and ioprio_set(2) from LP64."

Put them back for ARM32. Some pre-L blobs link with it
This partially reverts commit 607341e226912d95d03216483bdcef6f8d96f8b4.

Change-Id: If8503bd5624869ba071fdd21fa48cffb65617586
Merge remote-tracking branch 'upstream/android-5.0' into android-5.0
Omni sync... here we go again :-p