ALSA: synth: Select snd-emux-synth explicitly

Instead of the non-standard way to enable the build of snd-emux-synth
module inside Makefile, rewrite Kconfig to select the item explicitly
from each driver (sbawe and emu10k1).  This is the standard way.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/Kconfig b/sound/Kconfig
index d2fadbe..d7d2aac 100644
--- a/sound/Kconfig
+++ b/sound/Kconfig
@@ -110,6 +110,8 @@
 
 source "sound/x86/Kconfig"
 
+source "sound/synth/Kconfig"
+
 endif # SND
 
 menuconfig SOUND_PRIME
diff --git a/sound/isa/Kconfig b/sound/isa/Kconfig
index bf1ab34..ea8ecc5 100644
--- a/sound/isa/Kconfig
+++ b/sound/isa/Kconfig
@@ -389,6 +389,7 @@
 	def_tristate SND_SEQUENCER && SND_SBAWE
 	select SND_SEQ_MIDI_EMUL
 	select SND_SEQ_VIRMIDI
+	select SND_SYNTH_EMUX
 
 config SND_SB16_CSP
 	bool "Sound Blaster 16/AWE CSP support"
diff --git a/sound/pci/Kconfig b/sound/pci/Kconfig
index bc7acb4..9ac9326 100644
--- a/sound/pci/Kconfig
+++ b/sound/pci/Kconfig
@@ -482,6 +482,7 @@
 	def_tristate SND_SEQUENCER && SND_EMU10K1
 	select SND_SEQ_MIDI_EMUL
 	select SND_SEQ_VIRMIDI
+	select SND_SYNTH_EMUX
 
 config SND_EMU10K1X
 	tristate "Emu10k1X (Dell OEM Version)"
diff --git a/sound/synth/Kconfig b/sound/synth/Kconfig
new file mode 100644
index 0000000..dfe8950
--- /dev/null
+++ b/sound/synth/Kconfig
@@ -0,0 +1,2 @@
+config SND_SYNTH_EMUX
+	tristate
diff --git a/sound/synth/emux/Makefile b/sound/synth/emux/Makefile
index fb761c2..4599108 100644
--- a/sound/synth/emux/Makefile
+++ b/sound/synth/emux/Makefile
@@ -8,6 +8,4 @@
 snd-emux-synth-$(CONFIG_SND_PROC_FS) += emux_proc.o
 snd-emux-synth-$(CONFIG_SND_SEQUENCER_OSS) += emux_oss.o
 
-# Toplevel Module Dependencies
-obj-$(CONFIG_SND_SBAWE_SEQ) += snd-emux-synth.o
-obj-$(CONFIG_SND_EMU10K1_SEQ) += snd-emux-synth.o
+obj-$(CONFIG_SND_SYNTH_EMUX) += snd-emux-synth.o