audio: Allow using vendor extensions in surround formats (V5)

The 'surroundFormats' section must allow specifying
vendor-provided formats (vendor extensions). This has been
fixed in Audio HAL V7. Backporting to earlier versions.

Bug: 173647783
Test: atest VtsHalAudioV5_0TargetTest
Change-Id: Ic0eb09df927af243d56038a8a102f0607bbaafaf