Avoid C-style cast warnings

hardware/libhardware/include was being included with -isystem, which
hides warnings.  Use a macro to convert modules to hw_device_t** to call
the open function that works in C++ and C.

Bug: 32018017
Test: m -j
Change-Id: If68bf15581975f1217fcab366cef7bc784894641
diff --git a/include/hardware/sound_trigger.h b/include/hardware/sound_trigger.h
index e1abbc9..d7828ac 100644
--- a/include/hardware/sound_trigger.h
+++ b/include/hardware/sound_trigger.h
@@ -124,7 +124,7 @@
                                        struct sound_trigger_hw_device** device)
 {
     return module->methods->open(module, SOUND_TRIGGER_HARDWARE_INTERFACE,
-                                 (struct hw_device_t**)device);
+                                 TO_HW_DEVICE_T_OPEN(device));
 }
 
 static inline int sound_trigger_hw_device_close(struct sound_trigger_hw_device* device)