Selection of layout to use for pass-through rendering is ambiguous

[felicialim]

Section 7.3.2.1 says

Else, if there is an Audio Element with a loudspeaker_layout that matches the playback layout, use it.

"it" could be ambiguous, referring to the Audio Element or the loudspeaker_layout. It should be the loudspeaker_layout. A proposed rewording is:

• Else, if the Audio Element has a loudspeaker_layout that matches the playback layout, use the layer with that matching loudspeaker_layout.

• Else, use the layer with the next highest available loudspeaker_layout compared to the playback layout.

[sunghee-hwang]

LGTM