oss4: also accept formats not natively supported
Also accept formats that are not natively supported by the hardware, OSS4 can convert them internally. List the native formats first in the caps though, to express our preference for the native formats. We need this in order to support the case properly where the audio hardware supports only e.g. little endian PCM, but the host is big endian, since many audio elements only support native endianness and make the reasonable assumption that any audiosink will be able to handle audio in native endianness. Based on patch by Jerry Tan <firstname.lastname@example.org> Fixes #614317.