[RCAR] adjust asound.state for new BSP 3.21/YP3.1

[RCAR] adjust asound.state for new BSP 3.21/YP3.1

Alsa sound card name has changed in BSP 3.21 for YP3.1: old name 'ak4613' has
been replaced by 'rcarsound'.

Specific fix for Ebisu board also becomes useless (alsa-state.bbappenda) and
is removed.

This change adjusts the card name while keeping the volume levels as before:
* 20% on DVC Out
* 10% on DVC In

Bug-AGL: SPEC-3380

Change-Id: Ic23c9b4c218ab275d5bd299911886cb40ebc8dc1
Signed-off-by: Stephane Desneux <stephane.desneux@iot.bzh>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/24572
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>