Revert "binder: add missing binder_unlock()"

This reverts commit febf108e.

There is no binder_unlock() in this branch, so this patch needs to be
reverted.

Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>