hal: fix for voip volume setting when select_devices()

voip volume setting will not be applied correctly when select_devices()
since its usecase type won't necessary be voip_usecase
check for voip_usecase existance and not a capture type instead.

Bug: 110446256
Bug: 120052983
Test: self tested 20 times making a DUO video call

Change-Id: If3e6bc46be02a83ccf92bd56fc48a9c88c1e21bd
Signed-off-by: Yung Ti Su <andysu@google.com>