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>

sound/Kconfig

@@ -110,6 +110,8 @@ source "sound/soc/Kconfig"
 
 source "sound/x86/Kconfig"
 
+source "sound/synth/Kconfig"
+
 endif # SND
 
 menuconfig SOUND_PRIME

sound/isa/Kconfig

@@ -389,6 +389,7 @@ config SND_SBAWE_SEQ
 	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"

sound/pci/Kconfig

@@ -482,6 +482,7 @@ config SND_EMU10K1_SEQ
 	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)"

sound/synth/Kconfig

+config SND_SYNTH_EMUX
+	tristate

sound/synth/emux/Makefile

@@ -8,6 +8,4 @@ snd-emux-synth-objs := emux.o emux_synth.o emux_seq.o emux_nrpn.o \
 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