hal: update pcm ids for multi offload use cases

Pcm ids for secondary offload sessions are not mapped
properly for 8916 platform.
Use audio_platform_info.xml to update pcm ids.
Use separate xml file, audio_platform_info_extcodec.xml
for external codec since it's pcm ids are different.

CRs-Fixed: 842795
Change-Id: Id34e639b2c169e95f17400bc3141206dfc6ad0b9