Make header functions "inline" to avoid warning when unused.

Change-Id: Iefac44f3c0e1c3fd4b19833d9692744100f92e00
(cherry picked from commit 5e9febef197a9852c833a0aedc6bfee179c4ae9e)
diff --git a/services/audiopolicy/common/include/policy.h b/services/audiopolicy/common/include/policy.h
index a2327ee..e6a767f 100755
--- a/services/audiopolicy/common/include/policy.h
+++ b/services/audiopolicy/common/include/policy.h
@@ -60,7 +60,7 @@
  *
  * @return true if the device is a virtual one, false otherwise.
  */
-static bool is_virtual_input_device(audio_devices_t device)
+static inline bool is_virtual_input_device(audio_devices_t device)
 {
     if ((device & AUDIO_DEVICE_BIT_IN) != 0) {
         device &= ~AUDIO_DEVICE_BIT_IN;
@@ -78,7 +78,7 @@
  *
  * @return true if the device needs distinguish on address, false otherwise..
  */
-static bool device_distinguishes_on_address(audio_devices_t device)
+static inline bool device_distinguishes_on_address(audio_devices_t device)
 {
     return ((device & APM_AUDIO_DEVICE_MATCH_ADDRESS_ALL & ~AUDIO_DEVICE_BIT_IN) != 0);
 }