alsa: add asound.conf sample for double audio output through analog and HDMI

packages/audio/alsa/config/asound.conf.sample/asound.conf_double-analog-hdmi.sample

@@ -0,0 +1,68 @@
+pcm.!default {
+        type plug
+        slave {
+                pcm "both"
+        }
+}
+
+pcm.both {
+        type route
+        slave {
+                pcm multi
+                channels 4
+        }
+        ttable.0.0 1.0
+        ttable.1.1 1.0
+        ttable.0.2 1.0
+        ttable.1.3 1.0
+}
+
+pcm.multi {
+        type multi
+        slaves.a {
+                pcm "hdmi_hw"
+                channels 2
+        }
+        slaves.b {
+                pcm "analog_hw"
+                channels 2
+        }
+        bindings.0.slave a
+        bindings.0.channel 0
+        bindings.1.slave a
+        bindings.1.channel 1
+        bindings.2.slave b
+        bindings.2.channel 0
+        bindings.3.slave b
+        bindings.3.channel 1
+}
+
+pcm.hdmi_hw {
+        type hw
+        card 1
+        device 9
+        channels 2
+}
+
+pcm.hdmi_formatted {
+        type plug
+        slave {
+                pcm hdmi_hw
+                rate 48000
+                channels 2
+        }
+}
+
+pcm.hdmi_complete {
+        type softvol
+        slave.pcm hdmi_formatted
+        control.name hdmi_volume
+        control.card 1
+}
+
+pcm.analog_hw {
+        type hw
+        card 0
+        device 0
+        channels 2
+}