Simplify the format conversion code in PCM OSS emulation.
This patch also adds the support of 3bytes 24bit formats with linear
and mulaw, but they are not enabled in pcm_plugin.c yet.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

Modules: ALSA<-OSS emulation

Clean up pcm-oss plugin codes.
Removed dead codes, and simplified route/rate plugins.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!