audio policy: check volume device before setVoiceVolume

If the volume device setting is different from the current rx device, there is no need to call setVoiceVolume to change the call volume.

Bug: 376772314
Test: Manual
Switch to speaker mode quickly after initiating a call
(cherry picked from https://partner-android-review.googlesource.com/q/commit:ebcece6a374834a9dd0581bace727a4ba081b9c8)
Flag: EXEMPT bug fix
Merged-In: I60b360d0adcc940706405e6e9618bc40e0717436
Change-Id: I60b360d0adcc940706405e6e9618bc40e0717436