Allow sensor HALs to access ashmem memory regions.

Allow sensor HALs to access ashmem memory. This is needed to support
direct delivery of sensor samples to applications.

Test: CTS test for SensorsDirectMode pass.
Change-Id: I00e3c0a0e59d72f84ff48098ddf868c94695d616

public/hal_sensors.te

+#Allow sensor hals to access ashmem memory allocated by apps
+allow hal_sensors {appdomain - isolated_app}:fd use;