binder: Fix concurrency issue in target_thread wakeup

until wake_up_interruptible_sync returns, couldn't another thread
just take control of the CPU anyway before the return.
This call will also prevent a reschedule.

Should be use wake_up_interruptible() call to immediately reschedule
target_thread instead of using wake_up_interruptible_sync() to block
the target_thread until CPU available to run.

Also protect target_thread with spinlock.

Change-Id: Ib2702bc798bf6927cee753811b39032f0aefe166
Signed-off-by: Jignesh Patel <jignesh@motorola.com>
Reviewed-on: https://gerrit.mot.com/1264379


SME-Granted: SME Approvals Granted
SLTApproved: Slta Waiver
Tested-by: Jira Key
Reviewed-by: Igor Kovalenko <igork@motorola.com>
Submit-Approved: Jira Key