alsa-mixer: sb-omni-surround-5.1.conf: remove analog-surround-21, add Linux 4.3+ support

In 2.1 mode LFE is not actually working at all, so it is removed.
With Linux 4.3-rc1+ Mic/Line are hw:%f,0,0 as it should be: https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound/usb?id=5ee20bc792467d7d612157e0a9962765aa943b08
So now we support both Linux 4.2.x- and 4.3-rc1+ setups.
Also in Linux 4.3-rc1 S/PDIF input was detected incorrectly (there is no such hardware input), so it is not present in config.

src/modules/alsa/mixer/profile-sets/sb-omni-surround-5.1.conf

@@ -15,8 +15,12 @@
 
 ; Creative Sound Blaster Omni Surround 5.1
 ;
-; This sound card have Mic/Line in at hw:%f,1,0 - this is the main
-; difference from default.conf, also unsupported sections removed.
+; This sound card have Mic/Line in at hw:%f,1,0 on Linux prior to 4.3-rc1,
+; but starting from Linux 4.3-rc1 Mic/Line is at hw:%f,0,0
+; This config supports both cases.
+; Also by default there are some non-existing (physically) inputs
+; and outputs that are not present here.
+; And finally in 2.1 mode LFE is not working, so it is removed also.
 ;
 ; See default.conf for an explanation on the directives used here.
 
@@ -24,25 +28,20 @@
 auto-profiles = yes
 
 [Mapping analog-stereo-output]
-device-strings = front:%f hw:%f
+device-strings = front:%f
 channel-map = left,right
 paths-output = analog-output
 priority = 10
 direction = output
 
+; Linux 4.2.x- have microphone input as device 1
+; While Linux 4.3-rc1+ have microphone input as device 0
 [Mapping analog-stereo-input]
-device-strings = hw:%f,1,0
+device-strings = hw:%f hw:%f,1,0
 paths-input = analog-input-mic analog-input-linein
 channel-map = left,right
 direction = input
 
-[Mapping analog-surround-21]
-device-strings = surround21:%f
-channel-map = front-left,front-right,lfe
-paths-output = analog-output
-priority = 5
-direction = output
-
 [Mapping analog-surround-41]
 device-strings = surround41:%f
 channel-map = front-left,front-right,rear-left,rear-right,lfe