ASoC: rsrc-card: rename rsrc-card to simple-scu-card phase2

rsrc-card which is using DPCM feature was created for Renesas sound.
But not only Renesas, but many SoC can use this driver, because
it is based on simple-card driver.
To use it as more open driver, rsrc-card will be renamed to
simple-scu-card. In order to easy patch review, as 2nd step,
this patch adds new compatible "simple-scu-audio-card";

rcar-card used specific property, not "simple-audio-card",
but it should be now. Actually, rsrc-card is upstreamed driver,
but noone is using it on upstream. The user is only local,
and it is only me. Thus, there is no compatible break by this patch.
This patch uses "simple-audio-card" prefix.
And it removes rcar-card specifix compatible too.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>