ANDROID: binder: fix node sched policy calculation

We should use FLAT_BINDER_FLAG_SCHED_POLICY_MASK as
the mask to calculate sched policy.

Change-Id: Ic252fd7c68495830690130d792802c02f99fc8fc
Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Git-commit: 6cd26315
Git-repo: https://android.googlesource.com/kernel/common


Signed-off-by: Kyle Yan <kyan@codeaurora.org>